# What is the residence time?

The residence time is effectively the average length of time that an entity, in this case a water molecule, will remain in a reservoir. By definition, the residence time is the amount of material in the reservoir, divided by either the inflow or the outflow (they are equal when the reservoir is at equilibrium).

Then, what does MRT mean in pharmacokinetics?

Equations for the mean residence time (MRT) of drug in the body and related functions are derived for drugs which are intravenously administered into a one- or two-compartment system with Michaelis-Menten elimination.

Why is average residence time important?

Residence time: The amount of time (in years) required to replace a given ocean constituent by river supply. Residence times are important because they tell you how quickly or slowly an ocean constituent can respond to a change in the constituent supply or removal rates.

## What is residence time in injection molding?

Shot size is the amount of resin that can be injected into the mold. Residence time is the time that resin is in the barrel before being injected. Reducing the shot size on an injection molding machine does not necessarily mean a reduction in the residence time.

## What is residence time distribution?

The residence time distribution (RTD) of a chemical reactor is a probability distribution function that describes the amount of time that a fluid element could spend inside the reactor.

## Where is most of the water on Earth?

The ocean holds about 97 percent of the Earth’s water; the remaining three percent is found in glaciers and ice, below the ground, in rivers and lakes. Of the world’s total water supply of about 332 million cubic miles of water, about 97 percent is found in the ocean.

## Where does the water cycle start and end?

The water cycle has no starting point. But, we’ll begin in the oceans, since that is where most of Earth’s water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air.

## What are the five main processes involved in the hydrologic cycle?

Together, these five processes – condensation, precipitation, infiltration, runoff, and evapotranspiration- make up the Hydrologic Cycle. Water vapor condenses to form clouds, which result in precipitation when the conditions are suitable.

## Where is the majority of the Earth’s freshwater stored?

The left-side bar shows where the water on Earth exists; about 97 percent of all water is in the oceans. The middle bar shows the distribution of that three percent of all Earth’s water that is freshwater. The majority, about 69 percent, is locked up in glaciers and icecaps, mainly in Greenland and Antarctica.

## What is the hydraulic retention time?

The hydraulic retention time (HRT), also known as hydraulic residence time or t (tau), is a measure of the average length of time that a compound (ex. water) remains in a storage unit (ex.

## What is space time in reaction engineering?

Space time (or space-time) is the time necessary to process one reactor volume of fluid, given a particular set of entrance conditions. Commonly represented by the Greek letter τ, it is obtained by dividing the reactor volume by the volumetric flow rate entering the reactor.

## How long does the average water molecule stay in the atmosphere?

A drop of water may spend over 3,000 years in the ocean before evaporating into the air, while a drop of water spends an average of just nine days in the atmosphere before falling back to Earth.

## How long does water stay in the ground?

Ground: When the water precipitates to the earth, it can stay in a few places. If it comes to the ground, it will likely hang out there for a month or two, though some of it will trickle down as shallow groundwater, where it can stay for 200 to 300 years. Deep ground water can remain underground for 10,000 years.

## What is the difference between condensation and precipitation?

This is followed by condensation, which is the process by which water vapor is changed back into liquid water. Then, water becomes precipitation, which is water falling from the clouds as rain, freezing rain, sleet, snow, or hail.

## What is the 4 stages of water cycle?

There are four main stages in the water cycle. They are evaporation, condensation, precipitation and collection. Let’s look at each of these stages. Evaporation: This is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas).

## What are the five stages of the water cycle?

Hence it is quite important to understand and learn the processes of the water cycle.

• Step 1: Evaporation. The water cycle starts with evaporation.
• Step 2: Condensation. NASA: The Water Cycle [720p]
• Step 3: Sublimation.
• Step 4: Precipitation.
• Step 5: Transpiration.
• Step 6: Runoff.
• Step 7: Infiltration.
• For Students:
• ## How many steps are there in the water cycle?

I will be talking about the water cycle and what it is. And the 4 steps of the water cycle. Precipitation, Evaporation, Condensation, and Transpiration. Condensation is what forms clouds up in the sky.

## How does the water cycle?

If heat is added to water, it evaporates. In the hydrologic cycle, water from oceans, lakes, swamps, rivers, plants, and even you, can turn into water vapor. Water vapor condenses into millions of tiny droplets that form clouds. Clouds lose their water as rain or snow, which is called precipitation.

## What is the first stage of the water cycle?

The first stage of the water cycle is when moisture from the sea and plants is lifted into the atmosphere. As the sun beats down it warms the oceans, rivers and lakes. This causes the water to rise into the air as water vapour. This process is known as evaporation.

## What is the water cycle and why is it important?

Water is perhaps the most important component of any ecosystem. All living organisms need water to grow and survive. In an ecosystem, water cycles through the atmosphere, soil, rivers, lakes, and oceans. Some water is stored deep in the earth.

## What is the purpose of the water cycle?

The water cycle starts from bodies of water on Earth, like lakes, streams, and oceans. As water is heated by the sun, it evaporates into the atmosphere. When it does, it collects in clouds, condenses, and eventually returns to Earth as precipitation.

## Why water is so important to life?

Water is the solvent that transports many essential molecules and other particles around the body. These include nutrients and waste products from the body’s metabolic processes. Particles such as some ions and molecules need to be able to move around biological organisms.

## What is Ka in pharmacology?

Absorption rate constant (ka) definition. ka is determined directly, or indirectly, as the slope of the linear relationship between the logarithm of the amount un absorbed and t, when natural logarithms, i.e. logarithms to the base e, are used. The half-time for absorption is computed as 0.693/ka, i.e. ln 2/ka.

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