Sunday 24 January 2016

SCOPE OF INSTRUMENTATION IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY.

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Introduction: Instrumentation is used in almost every activity and generating system, where consistent and reliable operations are required. Instrumentation provides the means of monitoring, recording and controlling a process to maintain it at a desired state. A typical environmental activity yields many process variables that have to be measured and manipulated. Variables such as boiler level, temperature and pressure, turbine speed, generator output and many others have to be controlled prudently to ensure a safe and efficient station operation. Instrumentation is often referred to as the power behind scientific investigations.
This assignment also explains the general aspect of Quadrat Survey; its purpose and approach for ecological study.
Ecology is the scientific study of the distribution and abundance of life and the interactions between organisms and their natural environment. The Environment is a complete ecological units that function as natural systems without massive human intervention, including all vegetation, animals, microorganisms, rocks, atmosphere and natural phenomena that occur within their boundaries. Therefore an ecological investigation is that which is concerned with study of all the biotic (living) and abiotic (non living organisms) in an environment. But because the total land environment cannot be studied, for obvious reasons like population and time, samples have to be taken. An acceptable way of doing this is to conduct a Quadrat survey.
Instrumentation definition:
The meaning of instrumentation cannot be positioned to a particular discipline. It is not rigid, depending on whom or what is defining it. It is generally described as the study, development and manufacture of scientific instruments and equipment. In other words, instrumentation is simply defined as instruments and procedures used in collecting and analyzing data in a study. 
Types of Instrumentation for Environmental Studies 
Different types of data are required for different categories of environmental studies; hence different instruments and procedures for their data collection and analyses exist too. But for the sake of explanation, the different methods of data acquisition are described below: 
a. Instrumentation for field observations: Instrumentation for these includes land survey equipment, both analogue and digital. Instruments for analogue approach to field survey include tape, arrow, Gunter chain, etc. Digital instruments include Total Stations, Global Positioning Systems (GPS), geographic information systems (GIS).
There are also some indirect methods of extracting information, especially from aerial photographs and satellite imageries. 
Other categories of instrument for field surveys include samplers, which are of various types depending on the parameter to sample; air, water, sediment and soil samplers. We also have testers or field equipment for direct observation, including pH and electrical conductivity meters, quadrats; for vegetation sampling, tape, ball of string, scissors, clipboard, pens and paper.      
b. Instrumentation for laboratory analyses: In a particular application the selection of a technique will be based on the particular requirements:  
1. What species (parameters) are to be measured; 
2. Is the simultaneous determination of several parameters necessary; and 
3. What are the required accuracy, time resolution, and spatial resolution? 
4. Logistic requirements like power consumption, mounting of light sources or retro-reflectors or accommodation of the instrument on mobile platforms.  
Classification of laboratory equipment:
Laboratory techniques are both specialized and universal techniques. Specialized techniques allow only one parameter (specie) to be detected by an instrument, e.g. UV absorption detection. On the other hand universal techniques allow one to measure many species with one instrument.  
Another fundamental property of instruments is the spatial range of the measurements, usually expressed in terms of in situ or remote sensing measurements. While in situ measurements come close to the ideal to determine specie concentrations in a ‘spot’ in space that is usually very close to the instrument, remote sensing techniques allow one to make measurements from a large distance, perhaps as far as from a satellite instrument in the earth’s orbit. It thus usually gives averages of the concentration over a relatively large area.  
Remote sensing techniques always rely on the sensing of electromagnetic radiation. Examples of laboratory instruments belonging to either category include 
(i) Gas chromatographic (universal technique, in situ), (ii) optical spectroscopy (universal technique, in situ and remote sensing), (iii) mass spectrometry (MS), (iv) any other (in situ) technique, where the most commonly employed principles include chemiluminescence (e.g. for the detection of NO or O), photo acoustic detection, electrochemical techniques, matrix isolation), and chromatography (IC).
It is important that you note that field surveys equipment such as total stations, GPS and aerial and satellite sensors are also remote sensing devise. This is because they are a devise that obtain information from the real world surface without being in physical contact with the object from which information is being obtained. You will learn more in the subsequent unit.  

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