Report on New Product Range for Environmental Monitoring
Types of technologies available for environmental monitoring.
1. Physical principle guiding types of environmental measuring systems
Pressure is a force exerted on a surface per unit area, and atmospheric pressure is caused by gravity pushing down on air molecules (which happen to have its own mass) to the earth's surface. As a result of this 99% of the atmosphere is below 32 kilometers from the earth's surface. (http://www.enviropedia.org.uk/Atmosphere/Pressure.php).
Air exerts pressure on everything within or around it which is measured in Pascals (pa) or millibars (mb) which is equal to 100 pascals. As one moves away from the earth's surface, air pressure decreases exponentially.
Heat is a form of energy. When a substance contains heat, it exhibits the property that is measured as temperaturethe degree of "hotness" or "coldness." The amount of heat absorbed by or removed from a substance raises or lowers its temperature a definite amount. However, the amount of temperature change depends on characteristics of the substance. At the microscopic level, temperature is a measurement of the kinetic energy, or average speed of motion of a molecule. The unit for temperature is degrees Celsius (C), although in the United States, the Fahrenheit (F) is still in use. The Celsius scale is fixed by two points, the freezing and boiling point of water, which at normal atmospheric pressure are 0C and 100C respectively. The Kelvin temperature scale is the absolute temperature scale. Absolute zero, the coldest temperature possible in the universe, is 0K or -273C. One Kelvin is equivalent to one degree Celsius, so 0C is the same as 273K, and 15C is the same as 288K.
Temperature varies across the globe due to various factors such as altitude, season, time of the day, and topography. Temperature normally decreases with increasing altitude throughout the troposphere but sometimes temperature increases with height through a layer
This is the measure of the level of water vapor in the air i.e. degree of saturation (caused by evaporation of water) relative to the saturation amount the air can hold at a given temperature. It is normally expressed as a percentage. Temperature largely determines the maximum amount of water vapor air can hold (air molecules move in the space amongst air molecules) . Warm air can hold more water vapor than cool air.
Increase in air temperature increase its ability to hold water i.e. vapor density. So for example a constant volume of air with 100% relative humidity will get lower relative humidity as its being heated. Conversely, when air is cooled, it loses its ability to hold water vapor and its relative humidity increase until it reaches 100% this is called the DEWPOINT. Further cooling will condense some water vapor as the air cannot hold them.
Wind speed n direction
Wind is caused by air flowing from regions of higher pressure to lower pressure. Pressure changes in the atmosphere are caused by the warming and cooling of air by the sun. The Sun heats the surface of the Earth unevenly, so that in some places it is warmer while in other places it is colder. Since a cold air mass is denser than warm air, pressure decreases more rapidly with height in cold air than in warm air. When cold denser air is placed next to warm less dense air, wind results. In nature, regions of excess move toward regions of deficit. Nature is always trying to balance. The result of trying to balance and equalize pressure results in wind. The closer the high and low pressure areas are together, the stronger the "pressure gradient" (flow from high pressure to low pressure), and the stronger the wind.
The wind however, does not blow in a straight line from high to low pressure. In fact it follows a much longer path spiraling out from a high pressure centre and spiraling in towards a low pressure centre. This is caused by the Coriolis force which results from the rotation of the Earth which tends to deflect wind to the right in the Northern Hemisphere and to the left in the Southern Hemisphere, so that the wind flows around the high and low pressure areas (http://www.weatherquestions.com/What_causes_wind.htm)
Our planets climate systems, ecosystems, hydrologic systems, etc. is all dependent on the energy from the sun i.e. solar energy. This makes solar irradiation a critical and important environmental factor to be measures. Solar irradiation is defined as the amount of radiant energy emitted by the sun over time. It is measured in kWh/m2/day and read kilowatt-hours per square meter per day.
Solar irradiance received at the Earth's surface can be separated into two, direct and diffuse. Direct solar irradiance is a measure of the rate of solar energy arriving at the Earth's surface from the Sun's direct beam, on a plane perpendicular to the beam,. Diffuse solar irradiation is due to the fact that some of the energy is removed from the sun's beam as it passes through the atmosphere is redirected or scattered towards the ground - the rate at which this energy falls on a unit horizontal surface per second is called the diffuse solar irradiance
This sort of information is used to build up Insolation maps. Insolation (from INcoming SOLar radiATION) is a measure of solar energy received on a given surface area in a given time, and as seen in the map below, varies around the Globe. This is useful when setting up solar panels and also for understanding climatic changes.
Gases and particulates
Every living thing needs air to survive and the quality of the air around us is essential. Polluted air will have hazardous effects on the quality of life and will damage the buildings and sensitive plant and wild-life and human health as well. There are various compounds that pollute our air such as carbon monoxide, carbon dioxide, sulphur dioxide and nitrogen oxides (NOx), also organic and inorganic particulates.
Carbon dioxide CO2:- carbon dioxide is important to the atmosphere but in little proportion (approx 0.04% and rising fast) and It supports plant life. But in higher levels, will cause catastrophic effects on the planet. Swift increase in the carbon dioxide levels in the atmosphere is caused by human activities which is causing increase in global warming and green house effect.
Carbon monoxide CO: - is a colorless, odorless gas that is poisonous if inhaled. It is produced when carbon fuels are burned in the presence of too little oxygen or at too high a temperature. The majority of atmospheric carbon monoxide is caused by road transport. Smaller contributions come from processes involving the combustion of organic matter, for example in power stations and waste incineration. (http://www.enviropedia.org.uk/Air_Quality/Carbon_Monoxide.php)
Sulphur dioxide SO2:- Sulphur dioxide (SO2) is a colorless gas which can react on the surface of a variety of airborne particulates, is soluble in water and can be oxidised within airborne water droplets producing sulphuric acid and deposited as acid rain. Main sources of sulphur dioxide are fossil fuel combustion, smelting, manufacture of sulphuric acid, conversion of wood pulp to paper, incineration of refuse and production of elemental sulphur. Coal burning is the single largest man-made source of sulphur dioxide accounting for about 50% of annual global emissions, with oil burning accounting for a further 25 to 30%. Exposure to high concentrations of sulphur dioxide can cause respiratory illness, alterations in pulmonary defenses, and aggravation of existing cardiovascular disease. (http://www.enviropedia.org.uk/Acid_Rain/Sulphur_Dioxide.php)
Nitrogen oxides NOx:- is a collective term used to refer to two species of oxides of nitrogen: nitric oxide (NO) and nitrogen dioxide (NO2). Nitric oxide is a colorless, toxic, flammable gas with a slight odour. Nitrogen dioxide is a reddish brown, nonflammable, gas with a detectable smell. In significant concentrations it is highly toxic, causing serious lung damage with a delayed effect. Nitrogen dioxide is a strong oxidizing agent that reacts in the air to form corrosive nitric acid which is deposited as acid rain. Globally, quantities of nitrogen oxides produced naturally by bacterial and volcanic action, and lightning, outweigh man-made emissions due to fossil fuel combustion.
Particulates: - Particulate matter is a complex mixture of organic and inorganic substances, present in the atmosphere as both liquids and solids. Coarse particulates can be regarded as those with a diameter greater than 2.5 micrometres (m), and fine particles less than 2.5 micrometres. Coarse particles usually contain dust from road vehicles and industries. Fine particles contain the secondarily formed aerosols, combustion particles and re-condensed organic and metallic vapours. Particulates may be seen as the most critical of all pollutants, and some estimates particulates are responsible for up to 10,000 premature deaths in the UK each year. Fine particulates can penetrate deep into the lung and cause more damage, as opposed to larger particles that may be filtered out by the nose.
Sensors and systems (hardware) available for environmental measuring and how they work.
Since air is not solid, it cannot be weighed with conventional scales. Any instrument that measures air pressure is called a barometer. The first of which was constructed by EVANGELISTA TORRICELLI in 1643. He weighed the atmosphere by balancing it against a column of mercury. He immersed a tube, sealed at one end, into a container of mercury.
Atmospheric pressure then forced the mercury up into the tube to a level that was considerably higher than the mercury in the container. Torricelli determined from this experiment that the pressure of the atmosphere is approximately 30 inches or 76 centimeters (one centimeter of mercury is equal to 13.3 millibars). He also noticed that height of the mercury varied with changes in outside weather conditions. (http://www.physicalgeography.net/fundamentals/7d.html)
The Weather and aviation industry uses two types of barometers. The mercurial and aneroid
This is made up of a glass tube about 33 inches closed at one end with a mercury filled dish. Atmospheric pressure forces mercury to rise in the tube. At near sea level, the column of mercury rises to about a height of 29.92 inches. In other words, a column of mercury of that height weighs the same as a column of air having the same cross section as the column of mercury and extending from sea level to the top of the atmosphere.
Mercury is the heaviest substance available that remains liquid at ordinary temperatures. It permits the instrument to be of manageable size. Water could be used but at sea level the water column would be about 34 ft high.
The aneroid barometer was invented by, Lucien Vidie, in 1843. The principle of the aneroid barometer is the change in height of a sealed metallic chamber called an aneroid cell made from an alloy of beryllium and copper which has flexible upper and lower surfaces. The cell is partially evacuated and contracts or expands as pressure changes. One end of the cell is fixed, while the other end moves the registering mechanism. The coupling mechanism magnifies movement of the cell, driving an indicator hand along a scale graduated in pressure units
Aneroid barometers are less susceptible to shock and the transport problems associated with mercury instruments. (http://www.metcheck.co.uk/acatalog/barometers.html)
Meteorological observatories usually measure the temperature of the air near the surface of the Earth (troposphere). This is measured by a thermometer which is exposed to air but shielded from radiation or moisture, particularly a dry bulb thermometers placed in a Stevenson screen (a standardized well-ventilated white-painted instrument shelter) positioned 1.25-2 m above the ground by legs to avoid strong temperature gradients at ground level.
Bulb thermometers are based on the principle that liquid changes its volume relative to its temperature. Mercury is put in a small bulb extending into a tiny tube which is the calibrated according to which scale is desired. Mercury is used because it change in volume with temperature is quite noticeable compared with water and also because it doesn't freeze or boil
Instruments used to measure relative humidity are called hygrometers. They come in various forms and are classified in the way they work. An important use of hygrometers is in weather forecasting. Hygrometers are also used for monitoring the humidity in laboratories, storage areas, and manufacturing plants where specific levels of humidity must be maintained. Some hygrometers form part of devices called humidistat, which are used to control humidifiers or dehumidifiers for regulating the humidity of the air.
This consists of two thermometers mounted side by side. One wet and the other dry bulb thermometers. The wet bulb thermometer has small sleeve of muslin or candle-wick that is pulled over the mercury reservoir bulb so it will show a lower temperature than the dry bulb thermometer. The cloth is wetted and the water is then made to evaporate by blowing air over the cloth with a fan or by whirling the psychrometer in the air. As the water evaporates, the bulb is cooled. In general, the drier the air, the greater is the drop in temperature. The relative humidity is determined by comparing the readings of the two thermometers with published psychrometric tables or charts. (http://science.howstuffworks.com/hygrometer-info.htm)
Hair tension hygrometers:
Since hair length changes when humidity changes, Hair tension hygrometers consists of a number of human or horse hairs attached to a mechanical lever system. When humidity increases the length of the hairs becomes longer. This change in length is then transmitted and magnified by the lever system into a measurement of relative humidity.
These use substances e.g. lithium chloride which changes in resistance as humidity changes for measurement. Some capacitive sensors sense water vapor by applying an AC signal between two plates and measuring the change in capacitance caused by the amount of water vapor present. Others called Dew-point hygrometers use optoelectronic devices to monitor condensation on a mirrored surface that is being cooled. The temperature at which condensation occurs is compared with the air temperature. The temperature of the mirror is controlled by electronic feedback to maintain a dynamic equilibrium between evaporation and condensation on the mirror, thus closely measuring the dew-point temperature. (http://en.wikipedia.org/wiki/Hygrometer)
Anemometers are devices that measure wind speed and wind vanes are used to measure wind directions generally most wind measuring instruments will have both speed and direction measuring abilities and are called wind indicators. Wind indicators are not only used for meteorological purposes, but also in mines, tunnels, and ventilation systems; in aircraft wind tunnel testing and in aerial navigation.
Three Cup Anemometer
Developed by John Patterson in 1926, this is the most wildly used type of anemometer. Three Metal cups are attached to the ends of horizontal shafts mounted on a vertical pole. Wind catching in the cups causes them to revolve which in turn makes the shaft revolve. The vertical pole is connected to an electrical generator. The amount of current produced by the generator varies with the speed of the wind. The wind velocity is measured in miles per hour, kilometers per hour, or knots. Later in 1991, the three cup anemometer was further modified by the Australian Derek Weston to measure both wind direction and wind speed. adding a tag to one cup, causes the rotational speed to increase and decrease as the tag moves alternately with and against the wind. Wind direction is calculated from these cyclical changes in speed, while wind speed is as usual determined from the average speed. (http://en.wikipedia.org/wiki/Anemometer)
Propeller or windmill anemometers
These use propellers instead of cups. Smaller propellers are used to when air flow in ventilating shafts are to be measured. When used outdoors where wind direction changes it has to be connected to a wind vane because the propellers only indicate the correct velocity when facing the flow of wind. This is because the axis of rotation must be parallel to the direction of the wind and therefore horizontal. The vane, which also shows the direction of the wind, keeps the propeller properly aligned.
This Consists of an electrically heated very fine wire exposed to the wind. The wind's speed cools the wire. As the resistance of most metals is a function of its temperature, the wind speed is related to the current necessary to maintain the wire at a constant temperature. The hot-wire anemometer is used mainly in experimental work.
Is a microcomputer based wind sensor capable of measuring wind velocity up to three axes with reliable accuracy.
The instrument is designed to measure wind velocity specific for air turbulence around bridges, buildings, wind turbine sites, building ventilation control systems, meteorological and flux measurement sites by transmitting and receiving sonic signals along fixed orthogonal directions. The microcomputer electronics then processes this information and calculates the wind speed in three axes. Its response to wind velocity change is linear as well with a fast response since there are no moving parts like the cup and propeller anemometers.
Measurements of solar irradiance can be characterized by the range of wavelengths (or frequencies) they are sensitive to. The three types of measurements are broadband, wideband, and narrowband.
This is a device used to measure broadband solar irradiance on a planar surface i.e. the combined intensity of incident direct solar radiation and diffuse sky radiation. Its sensor is designed to measure solar radiation flux density in watt/meter square from a view of 180 degrees. The solar radiation spectrum extends approximately from 300 to 2,800 nm and Pyranometers are sensitive to that spectrum. A typical pyranometer does not require any power to operate and it does by comparing the heat produced by the radiation on black conical absorber with that produced by a known electric current.
The pyrheliometer is a broadband instrument that measures the direct (or beam) component of solar radiation at normal incidence. This means the instrument is always aimed directly at the sun, via a tracking mechanism that continuously follows the sun. It is sensitive to wavelengths in the band from 280 to 3000 nm. Solar irradiance enters the instrument through a sealed crystal-quartz window and the sunlight is directed onto a thermopile which converts heat to an electrical signal that can be recorded.
Gases and particulates
Gases and particulates are measured in industrial processes where operation efficiencies or safety standards are important, or for environmental monitoring thin film based gas sensors Polyaniline(PANI) based gas sensors
Nature of Environmental Monitoring systems market.
1. Products already in the market n patents if any
2. Review of possible markets for environmental monitoring systems
d. Environmental safety.
Company plan on entering Environmental monitoring market.
1. Identifying packages for individual market sector / industry(radiosones)
2. R&D efforts
3. Time line for R&D, manufacture, testing, release.
4. Cost for R&D by graduate engineers, manufacturing, testing, marketing.