0
Given the relative humidities at various temperatures, calculate the absolute humidities (in grains of water per pound of air) at those temperatures. The absolute humidity of the ambient air is the saturation humidity multiplied by the percentage relative humidity and divided by 100: Habs = (Hsat )(RH / 100) where: Habs = absolute humidity at a given temp Hsat = saturation humidity at the same given temp RH = percentage relative humidity at the same given temp First, you must calculate the saturation humidity at each of your temperature data points: Hsat = (7000)(18.02 / 28.85)(PS)/(Pamb - PS) where: Hsat = grains of water per pound of air 7000 = grains per pound 18.02 = molecular weight of water 28.85 = molecular weight of dry air (taken as 79 vol % nitrogen, 21 vol % oxygen) PS = vapor pressure of water at temperature T Pamb = ambient pressure (You will need a good set of steam tables to look up the vapor pressure of water at each of your temperature data points) Example calculation of Hsat at 68 oF and an ambient atmospheric pressure of 14.696 psia: From the steam tables, the vapor pressure of water is 0.3389 psia at 68 oF. Hsat = (7000)(18.02/28.85)(0.3389)/(14.696 - 0.3389) = 103.2 grains of water/lb of air Now if your relative humidity data point at 68 oF was say 60%, then: Habs = (103.2)(60/100) = 61.9 grains of water/lb of air It is quite easy to set up a spreadsheet to convert your relative humidity data as per the above example ... then all that would be needed is to enter the water vapor pressure values at each of your temperature data points.
You can also just use calculator apps to do it for you - like EZ Air: http://www.parkssoft.com/ezair.html
Add your answer:
Earn +20 pts
What is coarse grain in metals?
Fine grains are harder than coarse grains
What is ductile to brittle transition temperature of steel?
It varies. Firstly, it's only present in ferrittic steels like carbon steel, not in most kinds of stainless. Secondly, it depends on the grain size of the steel microstructure, with smaller grains giving a lower transition temperature. The third factor is alloying elements. Silicone and Nickel content tends to raise transition temperature. With modern steels the transition temperature is about -60 degrees celcius. Older steels may have a transition temperature at room temperature, or, more often, at 0 or -10 degrees.
Why is the compressive strength of wood more along grains?
it depends upon the sliding of fibers or grains on each other, if sliding is more so you will get more compressive strength.
What do countries export?
goods such as medicines, cloths, grains, other foods, timber, and automobiles
What are the various types of nutrients and their purpose?
Nutrient Function Sources Carbohydrates energy Potatoes, pasta, whole grains Minerals Regulate vital processes, necessary for formation of healthy bones and teeth Dairy, grains, vegetables Vitamins Help regulate digestion, absorption and metabolism of other nutrients Fruits, dairy, grains, nuts, meat Protein Growth, maintenance and repair of the body's cells, energy Fish, meat, eggs, milk, some soybean products Fats Regulate body temperature, supply energy, transport vitamins A, D, E, K in the blood, source of linoleic acid Fish, dairy, olive/canola/ soybean/cottonseed/corn oil Water Transports nutrients, carries waste from cells, vital to every body function Water, milk, juice, some fruits and vegetables
Compare relative humidity with absolute humidity?
Himidity is the amount of water vapor present in the air. Relative humidity is a measure of the amount of water vapor present in the air compared to the amount needed for saturation at a specific temperature
How do you preserve food grains?
Food grains are better preserved in air tight containers at low humidity and temperature
What unit of measurement measures humidity?
Water vapor in the air is absolute humidity. The ratio of the absolute humidity to the maximum absolute humidity for that temperature and pressure is called the "relative humidity." Absolute humidity is very frequently expressed in terms of grains per pound of air, ppm, or vapour pressure. Relative humidity is usually expressed as a percent.Relative humidity, expressed as a percentage from 0% to 100%, is the amount of moisture in air divided by the total possible amount of moisture in air. Unfortunately, the total possible amount changes when the temperature changes, so the relative humidity can change without adding or removing any water.Another measure is dew point, which is the temperature at which water would condense. It doesn't change with temperature.The lowest measured relative humidity in Phoenix, AZ, USA, is 2%--pretty dry. Sometimes the dew point is below 0 degrees, also pretty dry. (Celsius or Fahrenheit? Both!)
What air property is measured in grains?
The property measured in grains is the amount of moisture in the air, known as humidity. Grains per pound (GPP) is a common unit of measurement for humidity in the air.
What is the measure of the amount of water vapor in the air?
The measure of the amount of water vapor in the air is called humidity. Humidity can be expressed as relative humidity, which is the percentage of water vapor present in the air relative to the maximum amount of water vapor the air can hold at a given temperature.
Hi. Just wondering about storing seeds and grains here in Hawaii (North Kohala, Big Island). Thoughts?
Container with low humidity, cool temperature, darkness.
What is the definition of 'wet heating'?
The rise in temperature of stored food-grains due to the growth of moulds and fungi and germination of stored food-grains under high humidity conditions of air is called wet heating or damp grain heating.
Units for humidity?
Humidity is typically measured in two units: relative humidity expressed as a percentage, and specific humidity expressed as grams of water vapor per kilogram of air. Both units are used to quantify the amount of moisture present in the air.
How do you calculate from mg to grains?
Conversion: mg x 0.01543 = grains
Is dew is water vapor dropping from thunderstorms?
Dew is not water vapor dropping from thunderstorms. Dew forms when the air near the ground cools and cannot hold all of its moisture, causing the excess water vapor to condense into liquid water droplets on surfaces like grass or leaves. Thunderstorms involve the condensation of water vapor in the atmosphere to form clouds and precipitation like rain, rather than dew.
How do you calculate grain depression?
Grain depression is a reduction of the humidity ratio/specific humidity expressed as a difference between ambient air and the output of a dehumidifier. It can also be expressed between two area differentials. The calculation is made by finding the Humidity Ratio of each area. The Humidity Ratio (or specific humidity) can be found by using the psychrometric chart. Once found, the HR of the ambient air is reduced by the HR of the dehumidifier output giving a depression (or reduction of grains of water in the air) of the Humidity Ratio. In short, this shows how well the dehumidifier is functioning.
Does pollen die?
Pollen grains are reproductive cells of plants and can remain viable for long periods, depending on the plant species. Some pollen can survive for years, while others may only last a few hours. Factors such as temperature, humidity, and exposure to sunlight can affect the life span of pollen grains.
