1.1.INTRODUCTION:
Tripura is a state in North-East India which borders Bangladesh, Mizoram and Assam. It is surrounded by Bangladesh on its north, south and west: the length of its international border is 856 km (84 per cent of its total border). It shares a 53 km long border with Assam and a 109 km Long border with Mizoram. The state is connected with the rest of India by only one road (NH-44) that runs through the hills to the border of Karimganj District in Assam and then winds through the states of Meghalaya, Assam and North Bengal to Calcutta. The State of Tripura is located between 22°56"and 24°32"North latitude and between 90°09"and 92°20"East latitude. Tripura is a landlocked State. The total length of its border is 1018 km. It is connected with the mainland through Assam over a small strip of border of 53 km characterized with unfavourable terrain.
Grain size analysis: Particle size and shape and their distributions are critical properties of coating and filler pigments. Particle size can be measured by many different methods, but particle shape is more difficult to measure. Particle analyses by a microscope enable a forming of images of the particles. The images can be analysed by image processing programs and particle size and shape can be measured with many Parameters. Measuring of particle shape with other analysing methods is also evolved, but the methods are not comparable because they base on different techniques as measuring of particle size too. The main targets of this master’s thesis are development of particle shape analysing methods with scanning electron microscope and image analysis programs and comparison of results from different particle analysers.
Permeability test:Permeability is a soil property indicating the ease with which water will flow through the soil. Soil permeability is the property of the soil to transmit water and air. Permeability depends on the following factors:
1) Particle size distribution of the soil grains
2) Void ratio of the soil
3) Shapes and arrangement of pores
4) Degree of saturation
5) Properties of the pore fluid (especially viscosity)
Factors 1 through 4 are all co-dependent on the density of the soil.
There are four laboratory methods typically used for measuring the permeability coefficient:
•variable-head (falling-head) test
•the constant-head test (ASTM D 2434)
•the capillary method
•back calculation from the consolidation test
Generally, soils which contain 10% or more particles passing the No. 200 sieve are tested using the falling-head method. The constant-head method is limited to disturbed granular soils containing not more than 10% passing the No.200 sieve.
We will use both methods to test disturbed soil prepared using fine sand and silt particles.
SOIL TEST:Soil quality is the fitness of soil for use. It is assessed in the context of the soil’s inherent capabilities, the desired uses of the soil, and the scale of assessment. The goal of soil quality research is to learn to manage soil for long-term productivity and environmental integrity. Soil scientists have extensively examined characteristics such as organic matter, erosion rates, and nutrient availability. Focusing on soil quality has added a focus on the dynamic and biological character of soil. This means assessing soil processes such as nutrient and water cycling for clues about short- and long-term soil function. Studying soil quality is about site-specific land management decision-making, rather than general land use assessment. The result of soil quality research is not a map of optimal land uses and a prescription for optimal land management. Instead the result of soil quality research should be many maps of soil conditions over time, an understanding of the processes that tie management to soil performance so that managers can make better site-specific decisions, and more direct linkages between the work of farmers and researchers. Soil quality is inextricably linked to sustainability (Doran et al. 1996). Understanding soil quality means reading and managing the soil so that it functions optimally now and is not degraded for future use.
Term of “Soil Quality” As the field of soil quality research expands; several good specific definitions have emerged. “The capacity of a soil to function within its ecosystem bound- Aries and interacts positively with the environment external to that ecosystem.” Larson and Pierce 1991,“The state of existence of soil relative to a standard, or in terms of a degree of excellence.” (This definition was used for moni-toring soil quality using statistical quality control methods.)Larson and Pierce 1991,“The capacity of soil to function within ecosystem boundaries to sustain biological productivity, maintains environmental quality, and promotes plant and animal health.” Doran and Parkin, The continued capacity of soil to function as a vital living system, within ecosystem and land-use boundaries, to sustain biological productivity, maintain the quality of air and water environments, and promote plant, animal, and human health.”Doran et al. 1996,