What effects residence time?

What effects residence time?

In size-exclusion chromatography, the residence time of a molecule is related to its volume, which is roughly proportional to its molecular weight. Residence times also affect the performance of continuous fermentors.

What factors affect the groundwater?

Natural factors, such as topographic position and the mineral composition of underlying geology, act to produce basic physical and geochemical conditions in groundwater that are reflected in physical properties, such as pH, temperature, specific conductance, and alkalinity, and in chemical concentrations of dissolved …

How does residence time depend on the size of a reservoir?

Residence time depends on the rate of out- flow and on the size of the pool. Residence time is the mathematical inverse of turnover rate.

What is the residence time of water in aquifers?

In the deeper aquifers, estimates of ground-water residence times typically were several thousand years but ranged from modern to 4,550 years.

What does it mean to say the residence time of water in the atmosphere is nine days?

Water stored in the soil remains there very briefly, because it is spread thinly across the Earth, and is readily lost by evaporation, transpiration, stream flow, or groundwater recharge. After evaporating, the residence time in the atmosphere is about 9 days before condensing and falling to the Earth as precipitation.

What is residence time distribution function?

RTD (Residence Time Distribution) Function (E(t)) = Fraction of molecules exiting the reactor that have spent a time between (t) and (t + dt) in the reactor.

What conditions affect groundwater availability?

The availability of groundwater as a water source depends largely upon surface and subsurface geology as well as climate. The porosity and permeability of a geologic formation control its ability to hold and transmit water.

What are the problems related to groundwater availability?

Depletion of water tables, saltwater encroachment, drying of aquifers, groundwater pollution, water logging and salinity, etc. are major consequences of overexploitation and intensive irrigation. It has been reported that in many parts of the country the water table is declining at the rate of 1–2 m/year.

How does residence time affect the quality of water?

The water residence time in the systems might be responsible for decay of water quality in the distribution system [1,2] and this could aid microorganism’s growth, thus causing undesirable effects on water quality and water beauty.

How does the residence time of water correlate to the size of a reservoir in the hydrologic cycle?

residence time: Tr = V/I [T], a measure of the average time a molecule of water spends in a reservoir. The residence time defined for steady-state systems is equal to the reservoir volume divided by the inflow or outflow rate.

What controls groundwater residence time?

The nature of geologic material strongly influences the velocity of groundwater flow and thus influences the travel and residence time. Velocities in the three broad classifications of geologic materials (granular sediments, fractured rock, and cavernous karst) are generally much different from one another.

What is the residence time in the atmosphere?

expressed in terms of the residence time, the average time spent by a molecule in the atmosphere after it leaves a source and before it encounters a sink.

What is residence time of groundwater?

Residence Time of Groundwater. The length of time water spends in the groundwater portion of the hydrologic cycle may be as little as days, or as much as 10,000 years or more. This is called “residence time.” For example: A raindrop may fall to the earth’s surface. It may seep down through the soil to a saturated zone or aquifer only…

How long does water stay in the ground?

Residence Time of Groundwater. The length of time water spends in the groundwater portion of the hydrologic cycle may be as little as days, or as much as 10,000 years or more.

Does groundwater spend more time in the subsurface?

Figure 38 – Groundwater flowing along longer, slower and deeper paths spends more time in the subsurface, so it has a longer residence time when it reaches the stream.

How do you calculate residence time in hydrologic cycle?

Residence time in any compartment of the hydrologic cycle is estimated as the volume of water in a compartment divided by the average flux of water into and out of that compartment. The exact values are uncertain, but their order of magnitude is easily estimated.

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