What is Fly Levels in Surveying?
Gunia means simply a diagonal checking of the rectangular area.
Gunia means simply a diagonal checking of the rectangular area.
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What is Gunia in Building Construction?
What is the criteria for the location of the head works in the irrigation system?
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For deciding the location of headwork an irrigation system, you should have to follow points during the selection of location. Elevation of water should be in such a manner that the water will flow under the gravity force. All the construction materials should be available in the surrounding area. DRead more
For deciding the location of headwork an irrigation system, you should have to follow points during the selection of location.
- Elevation of water should be in such a manner that the water will flow under the gravity force.
- All the construction materials should be available in the surrounding area.
- Diversion head should be near the irrigation for irrigating area as possible and for keeping minimum canal length.
What are Various properties and optimization of alkali activated fly ash?
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Properties of alkali-activated fly ash : I studied different research papers based on the above topic and I concluded that : The mortar and concrete made with Portland cement, free activated fly ash develop a highest mechanical strength Less time required to gain enough strength It has a moderate mRead more
Properties of alkali-activated fly ash :
I studied different research papers based on the above topic and I concluded that :
- The mortar and concrete made with Portland cement, free activated fly ash develop a highest mechanical strength
- Less time required to gain enough strength
- It has a moderate modulus of elasticity
- Better Bond formation of Steel reinforcement
- Its shrinkage capacity is very less as compared to ordinary Portland cement concrete
Optimisation of alkali-activated fly ash :
- Actually conductive alkali-activated Ash is formed using carbon fibres
- Optimisation of alkali-activated fly ash is done when we use 0.3% Carbon fibre content 25 to 30 per cent ceramsite content and 70% slag content
Thank you.
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What is Pozzolana Reaction?
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Pozzolanic reaction is the reaction which continue to occur as long as calcium hydroxide is present, there is sufficient water for the reaction to occur, and there is available space for the reaction products to reside.
Pozzolanic reaction is the reaction which continue to occur as long as calcium hydroxide is present, there is sufficient water for the reaction to occur, and there is available space for the reaction products to reside.
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Derive the expression to find the distance and elevation of the object when the base of the object is inaccessible? Consider instruments and objects lies in the same vertical plane.
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When the base of the object is inaccessible we use an indirect method of surveying. A tachometer is used to measure the distance between the two points with the use of an analytical lens. There are two methods Stadia method: In this method diaphragm of the tachometer are provided with two stadia haiRead more
When the base of the object is inaccessible we use an indirect method of surveying.
A tachometer is used to measure the distance between the two points with the use of an analytical lens. There are two methods
- Stadia method: In this method diaphragm of the tachometer are provided with two stadia hair .the difference between staff intercept gives stadia reading.
- Tangential Method: in this method, the tachometer is not provided with stadia hairs, the reading is taken by single horizontal hair.
D=(f/L)S + (f + d)
D=horizontal distance between tachometer and stadia rod.
f/L = multiplying constant
S= Staff Intercept
Elevation formula:
v = KSsin(2©)/2 + Ccos(2©)
© = Theta= Angle of elevation or depression.
K & C = Tachometric Constant
substance method and tangential method is also used to find the elevation between two points.
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Describe the detailed classification of water application methods. State the advantages and disadvantages of each method.
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Based on energy/pressure reqd Gravity Irrigation. Border, basin & furrow irrigations Pressurized irrigation. Drip & Sprinkler irrigations Based on placement of irrigation water (on, above or below soil surface) Surface irrigation. Border, basin & furrow irrigations Subsurface irrigationRead more
- Based on energy/pressure reqd
Gravity Irrigation. Border, basin & furrow irrigations
Pressurized irrigation. Drip & Sprinkler irrigations
- Based on placement of irrigation water (on, above or below soil surface)
Surface irrigation. Border, basin & furrow irrigations
Subsurface irrigation
Overhead irrigation. Sprinkler & hand watering
- Based on wetted area of crop root zone by irrigation
Flood irrigation (Border, basin & furrow)
Drip (or trickle or localized) irrigation
Sprinkler irrigation
Surface Irrigation Method: Borders
- Best adapted to grain and forage crops
- Good for uniform soils with mild slope
- Not good for crops sensitive to wet soil conditions
- Typical efficiencies range from 70 – 85%
- Major investment is that of land grading or leveling
- Border strip width, W = 3 – 30m; Length, L = 100 —- 800m
- Has zero side slope and uniform longitudinal slope of <1%
- Strips have no cross slope
Surface Irrigation Method: Basins
- Field is divided into small units surrounded by levees or dikes
- Basin size: 1 to 15 ha; up to 100 to 400 m long
- Most commonly practiced for rice and orchard tree crops
- Level basin
- Water is held until it infiltrates or is drained away
- Minimum runoff loss and High application efficiency is possible
- Graded basin (contour levee irrigation)
- Constructed with two levees parallel and two perpendicular to the field contours
- Water enters along the upper contour and flows to the lower.
Advantages
- Water covers the basin rapidly to ensure good uniformity
- Best suited for lands/crops where leaching is required to wash out salts from the root zone
- Involves the least labour of the surface methods
- Design efficiencies can be on the order of 70-85%
Limitations
- Levees interfere with movement of farm equipment
- Higher amount of water is required compared to sprinkler or drip irrigation
- Amajor cost in basin irrigation is that of land grading or leveling
- Impedes surface drainage
Surface Irrigation Method: Furrow
- Irrigation is accomplished by running water in small channels (furrow)
- Constructed with or across the field slope
- Water infiltrates from the bottom and sides of furrows moving laterally and downward to wet the soil and to move soluble salts, fertilizer and herbicides carried with the water
- Widely spaced row crops such as potato, maize, vegetables, and trees
- Loam soil with mild slope, 0.5-2%
- Labour reqd is generally higher
- Major initial cost is construction of furrow
Types
- Level
- Graded
- Contour
Advantages
- Efficiency can be high.as 90%
- Developed at a relatively low cost after necessary land-forming activities are accomplished
- Erosion is minimal
- Adaptable to a wide range of land slopes
Limitation
- Not suitable for high permeable soil where vertical infiltration is much higher than the lateral entry
- Higher amount of water is required, compared to sprinkler or drip irrigation
- Furrows should be closely arranged
Sprinkler Irrigation
- Water is delivered through a pressurized pipe network to sprinklers, nozzles, or jets which spray the water into the air, to fall to the soil as an artificial “rain”
- Light sandy soils are well suited
- Sprinklers can be used on any topography
- Sometimes used to germinate seed and establish ground cover for crops like lettuce, alfalfa, and sod
- Very high efficiency water application
- High capital investment but has low labor requirements
Types
- Portable or hand move
- Solid set & permanent
- Travelling gun system
- Side roll system
- Centre pivot & linear move system
Advantages
- Readily automatable
- Facilitates to chemigation and fertigation
- Reduced labor requirements needed for irrigation
Limitations
- Many crops (citrus, for example) are sensitive to foliar damage when sprinkled with saline waters
- Initially high installation cost
- High maintenance cost
Drip Irrigation
- Constant steady flow of water is applied directly to the root zone of the plants by means of applicators operated under low pressure
- Applicators: orifices, emitters, porous tubing, perforated pipe
- Most efficient irrigation system
- Most suited to high-density orchards, tree crops, and high-value horticultural crops
- Not designed for large root systems
- Suited for situations where the water supply is limited
- Very effective in applying nutrients (fertilizers)/insecticides through the drip system
- Burying the drip system reduces water loss even further by preventing runoff across the surface
Advantages:
- Highly efficient system
- Limited water sources can be used
- Right amount of water can be applied in the root zone
- It can be automated and well adapted to chemigation and fertigation
- Reduces nutrient leaching, labor requirement, and operating cost
- Nearly uniform distribution of water
- Lower pressures are required-low energy for pumping
Limitations:
- High initial cost
- Technical skill is required to maintain and operate the system
- The closer the spacing, the higher the system cost per hectare
- Damage to drip tape may occur
- Cannot wet the soil volume quickly (to recover from moisture deficit) as other systems
- Facilitates shallow root zone
- Needs clean water
Other Forms of Irrigation
Hand watering
- Nurseries and Fruit trees
Capillary irrigation
- Wet the root zone by capillary rise
- Buried pipes or deep surface canals
Localized irrigation
- Water is applied around each or group of plants
- Wets root zone only
Subsurface irrigation
- Water is applied below the ground surface either by raising the water table within or near the root zone or by using a buried perforated or porous pipe system
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What are the design features for ‘Furrow Irrigation’?
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In this, water is applied through series of long, narrow, field channels called Furrows. Small furrows called corrugations. Water flowing through furrows infiltrates into the land/soil and spreads laterally to roots of plants. Crops are grown on ridges, levees. Evaporation losses reduces up to someRead more
- In this, water is applied through series of long, narrow, field channels called Furrows.
- Small furrows called corrugations.
- Water flowing through furrows infiltrates into the land/soil and spreads laterally to roots of plants.
- Crops are grown on ridges, levees.
- Evaporation losses reduces up to some extent.
- Suitable for row crops such as maize. Longitudinal slope of furrow – 0.6 – 0.8%
Soumyadeep Halder
Fly levelling it is a very approximate form of levelling in which sights are taken as largeas possible. In this method a line of levels is run to determine approximately reduced levelsof the points carried out with more rapidly and less precision. It is a levelling that is done toconnect bencRead more
See lessFly levelling
it is a very approximate form of levelling in which sights are taken as largeas possible. In this method a line of levels is run to determine approximately reduced levelsof the points carried out with more rapidly and less precision. It is a levelling that is done toconnect benchmark to the starting point of the survey line. In this levelling only back sightand fore sight readings are taken and auto level is moved strictly on the line joining benchmark and starting point of survey line