KUCH AISA KARKE DIKHA KHUD KHUSH HO JAE KHUDA (EXAM SHOULD BE YOUR JUNOON)
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Thursday, 5 August 2021
Wednesday, 4 August 2021
Target GATE & ESE 2022 (Geomatics Engineering)
👉The correct sequence of the survey is
(a) Traffic survey
(b) Reconnaissance survey
(c) Preliminary survey
(d) Detailed survey or location survey
👉Topographical survey is done to determine information about man made and natural features on earth surface including their elevations.
👉Reconnaissance survey is a kind preliminary survey which is performed to find out method of survey to be adopted and its rough cost.
👉Cadastral survey is done to establish property boundaries.
👉Archaeological survey is done to collect information about old and relic structures.
👉 Transverse surveying is done with the help of compass and chain.
👉Geodetic surveying (Curvature of earth is taken into account) is done with the help of precise instruments such as Theodolite
👉Weddle sounding machine is used to determine depth of sea in hydrographic surveying.
👉The principal of surveying is work from whole to part.
👉 Various instruments used in surveying and their purpose:
- Pegs: To mark survey station and end points of survey lines on the ground
- Ranging Rod: For locating a number of points on a long survey line
- Offset rods: To set out offset line at right angles
- Prism Square: Setting out right angles
- Clinometer: To measure the slope of ground
- Optical Square: To set out right angles
- Prismatic Square: Advanced version of Optical Square and used to set out right angles
- French Cross Staff: Used to set out either 45 degree or 90 degree
- Open Cross Staff: Type of cross staff which is also used to set out 90 degree
- Theodolite: To measure of all horizontal and vertical angles
- Dumpy Level: Measurement of angle and elevation
- Auto Level: For Levelling purpose
Fig 1. Optical Square
Fig.2 French Cross Staff
👉Offsets are lateral measurement made w.r.t main survey line which may be oblique or perpendicular in nature.
👉The main objectives of cross staff survey is:
- To locate boundaries of an area
- To plot the figure to a scale
- To find area of the piece of land to be surveyed.
- Pacing
- Passometer
- Pedometer
- Odometer
- Measuring wheel
- Speedometer
- Perambulator
Fig 3. Passometer
Fig 4. Pedometer
Happy Learning
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Tuesday, 3 August 2021
Target ESE 2022 (Basics of Material Science & Engineering)
👉Atoms are made of electron, proton and neutrons.
👉 Electrons and protons are negative and positive charged particles respectively. The magnitude of each charged particle in an atom is 1.6 x 10^-19 Coulombs.
👉The mass of electron is negligible as compare to proton and neutron.
👉The unit of mass is an atomic mass unit
1 a.m.u = 1.66 x 10^-27 kg
👉Matter is composed of tiny particles called atoms.
1. Stable particles: Electron, proton and neutron
2. Unstable particles- positron, neutrino, anti-neutrino and meson
3. Composite particles- Deuteron and alpha- particles
👉Electron: It carries a very small negative electrical charge.
It has negligible mass i.e. its mass is 1/850th of the mass of hydrogen atom.
👉Proton: It carries small positive electrical charge.
Mass of each proton is same as that of hydrogen atom.
Protons are also present in all all the atoms.
👉Neutron: It does not carry any electrical charge. Its mass is equivalent to that of proton.
👉 Positron or positive electron: The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1 e
👉Meson: The mass of meson is in between the mass of electron and proton.
Mesons were discovered during cosmic ray studies.
👉 There are two types of meson (i) p-meson which is heavier (ii) m-meson which is light
👉Both type of mesons may be either negatively or positively charged.
👉Deuteron: It is positively charged.
It is heavy hydrogen nucleus.
👉 Alpha Particles: They are double charged helium nucleus.
They appear as product of radioactive decay.
👉Meson carries a either negative or positive charged.
👉The weight of an electron is 1/1836 of the weight of proton or neutron.
👉Avogadro Number(N) = 6.023 x 10^23
👉Mean distance between atoms in the range of 0.23 nm.
Happy Learning
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Target ESE 2022 ( Basics of Energy and Environment)
👉 Ecology: Study of ecosystem.
👉Ecosystem: It was coined by A.G Tansley
👉Environment: Everything that surrounds or affects an organism during its life time is collectively known as its environment. It comprises both living (biotic) and non-living (abiotic) components.
👉Components of Environment
Abiotic (Non-living) Biotic (Living)
Energy Green plants
Radiation Non-green plants
Temperature & heat flow Decomposers
Water Animals
Soil Man
👉When an ecosystem is healthy (i.e. sustainable) it means that all the elements live in balance and are capable of reproducing themselves. Ecosystem can be as small as a single tree or as large as entire forest.
👉Types of ecosystem
(i) Natural (ii) Artificial (e.g. Zoo, aquarium, gardens)
👉 Natural ecosystem can be classified as
(a) Terrestrial (e.g. Forests, Grasslands, deserts) (b) Aquatic (e.g. Lakes, Rivers, Oceans, Ponds)
👉Ecotone: Transition zone between two different zones of ecosystem.(Ecotone is a zone of junction between two or more diverse ecosystems)
e.g. Mangrove forests represent an ecotone between marine and terrestrial ecosystem
e.g. Coastal region, wetlands
👉 Characteristics of Ecotone
- It may be very narrow or quite wide
- It has the conditions intermediate to the adjacent ecosystems. Hence it is a zone of tension
- It is linear
- A well developed ecotones contain some organisms which are entirely different from that of the adjoining communities.
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Sunday, 1 August 2021
Target GATE & ESE 2022 (Building Materials)
Do you Know?
👉Blaine's Air Permeability apparatus is used to test fineness of cement.
👉Vicat's needle is used to determine the setting time of cement.
Fig 2. Vicat's Apparatus
👉Soundness of cement is determined by Le-Chatelier apparatus.
Fig 3. Le-Chatelier Apparatus
👉According to IS 4031 Part 5, the initial setting time is conducted on cement by gauging the cement with 0.85 times the water required to give a paste of standard consistency.
👉Low heat portland cement can be used for mass concreting in very large structure while rapid hardening portland cement is unsuitable for it.
👉Gypsum is used in the cement grouts for retarding the setting time.
👉According to IS code for an ordinary portland cement (OPC), the initial setting time should not be less than 30 minutes and the final setting time should not be more than 10 hours (600 minutes)
👉Fine grinding leads to high early strength.(the finer the cement the higher is the rate of hydration which results in early development of strength.)
👉The temperature range in a cement kiln is 1300 to 1500 degree centigrade.
👉Specific gravity of cement is determined by using Le Chatelier's flask.
👉In OPC following are the proportion of oxides
Cao ---------- 63%
SiO2 ----------- 20%
Al2O3----------- 6.3%
Fe2O3------------- 3.60%
MgO-------------- 2.40%
👉 Following is the compound composition in OPC
Compound Wt %
Tricalcium silicate, C3S(Alite) 45-60
Dicalcium silicate,C2S (Belite) 15-30
Tricalcium aluminate, C3A 6-12
Tetracalcium aluminoferrite, C4AF 6-8
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Saturday, 31 July 2021
Target GATE & ESE 2022 Revision Test
Q.1 A stream function is given by ψ = 3x^2 -y^3. What is the magnitude of velocity components at the point (2,1) ?
(a) 8.52 (b) 9.17
(c) 10.81 (d) 12.37
Q.2 What is the minimum size of glass tube that can be used to measure water level if the capillary rise in the tube is to be restricted to 2 mm ? (Take surface tension of water in contact with air as 0.073575 N/m)
(a) 1.5 cm (b) 1.0 cm
(c) 2.5 cm (d) 2.0 cm
Q.3 What is the hydraulic radius of a stable canal carrying a discharge 0f 27 m^3/s using Lacey's method? (Assume silt factor is unity)
(a) 1.44 m (b) 2.67 m
(c) 3.14 m (d) 4.28 m
Q.4 Which one of the following is the correct assumption of Rankine's theory?
(a) The soil mass is infinite
(b) The soil mass is non homogeneous
(c) The soil mass is cohesive
(d) The ground surface is a plane which may be horizontal or inclined
Q.5 Which one of the following is not an instrument for setting out right angles?
(a) Cross staff (b) Site square
(c) Prism square (d) Optical square
Q.6 The hardness of aggregate is tested by
(a) Impact test (b) Crushing strength test
(c) Abrasion test (d) Soundness test
Q.7 The drawback of electric seasoning of timber is
(a) Checks (b) Splitting
(c) Cracks (d) Reduced Strength
Q.8 Pozzolanas are
(a) argillaceous materials
(b) calcareous materials
(c) accelerators
(d) siliceous materials
Q.9 A plane element in a body is subjected to a tensile stress of 100 MPa and shear stress of 25 MPa. What is the normal stress on a plane inclined at 15 degree with the tensile stress?
(a) -5.8 MPa (b) -4.8 MPa
(c) -3.8 MPa (d) -2.8 MPa
Q.10 If the pressure head of water is 100 m and specific gravity of kerosene is 0.81, what is the pressure head of kerone?
(a) 123.5 m of kerosene (b) 241.3 m of kerosene
(c) 75.1 m of kerosene (d) 52.4 m of kerosene
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Target GATE & ESE 2022 (Geotechnical Engineering)
Do You Know?
👉 In-Situ Shear modulus of soil can be calculated from Pressure-meter test.
👉 Soil Consistency N-Value
Very Soft 0-2
Soft 3-4
Firm 5-8
Stiff 9-16
Very Stiff 16-32
Hard >32
👉 Soil Description Relative Density(%) N-Value
Very Loose <15 <4
Loose 15-35 4-10
Medium Dense 35-65 10-30
Dense 65-85 30-50
Very Dense >85 >50
👉 SPT: Suitable only for Cohesionless soil such as sandy soil
DCPT: Dynamic cone penetration test is conducted by driving the cone by blows of a hammer. This is primarily used for cohesive soils but also applicable for medium to fine sand.
SCPT: Static Cone penetration test is used for soil profiling. It also gives the value of end resistance and frictional resistance of sleeves.
👉Auger boring is most effective in soft soils which can stand unsupported and have some stickiness so that they do not fall back into hole during lifting operation.
👉Geophysical methods: They are non-destructive methods used in the construction industry for investigation of sub surface.
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Happy Learning
Friday, 30 July 2021
Target GATE & ESE 2022 (Geotechnical Engineering)
Q.1 If an SPT test gave the average blow count of 32 in fine sand below water table, then what is the corrected value of blow count?
(a) 22.1 (b) 23.5 (c) 24.2 (d) 24.8
Q.2 On which of the following soils is the standard penetration test useful?
A. Cohesionless soil B. Medium clay
C. Gravelly soils D. Very stiff clays
Select the correct answer using the code given below
(a) A only (b) A and C
(c) A and B (d) C and D
Q.3 The standard penetration resistance value obtained in a deep deposit of sand at a depth of 6 m was 28. The unit weight of sand is 18 kN/m^3. What is the corrected value of number of blows for overburden pressure?
(a) 60 (b) 57
(c) 59 (d) 55
Q.4 Consider the following statements:
1. Standard penetration test is commonly used for cohesionless soils.
2. Standard penetration test results in respect of a cohesionless soil are correlated to its density index and friction angle.
3. Use of N-value not corrected for overburden pressure leads to highly conservative design of footing at shallow depths.
Which of the following statements are correct?
(a) 1,2 and 3 (b) 1 and 2 only
(c) 2 and 3 only (d) 1 and 3 only
Q.5 During a sampling operation , the drive sampler is advanced 600 mm and the length of sample recovered is 525 mm. What is the recovery ratio of the sample?
(a) 0.125 (b) 0.140
(c) 0.875 (d) 0.143
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Wednesday, 28 July 2021
Target GATE & ESE 2022 (Geotechnical Engineering)
Do You Know?
👉 For a good quality soil sampler all the parameters mentioned below should be low.
Area ratio 10% or less
Inside clearance 0.5-3%
Outside clearance 0-2%
👉 For soft sensitive clays, an area ratio of 10% or less is preferred.
👉
- Chunk samples are considered as undisturbed samples.
- Remoulded sampler tends to disturb the soil structure completely
- Split spoon sampler is a thick tube type of an open driven sampler with an area ratio around ratio 30%, so the samples collected are of the disturbed type
- Piston sampler is a thin tube type sampler and excellent tool for obtaining very fine undisturbed samples, especially in soft sensitive clays.
👉 Rotary Sampler: It is double walled tube sampler. The outer tube (rotating barrel) is having a cutting bit so they can be used in hard cohesive soils and rocks.
👉Stationary piston sampler: Very much suited for sampling in soft soils and saturated sands.
👉Recovery Ratio(R.R): Ratio of recovered length of sample to penetration length of sampler.
If R.R = 1 Good recovery
If R.R <1 soil in sample is compressed
If R.R >1 soil has swelled
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Target GATE & ESE 2022 (Fluid Mechanics)
Do You Know?
👉
- Hot Wire Anemometer: It is used for measurement of instantaneous velocity and temperature at a point in flow but it is an ideal tool for measurement of velocity fluctuations in time in turbulent flow.
- Orifice Meter: It is cheap device which is used to measure the volume flow rate means discharge.
- Pitot Tube: Used for measurement velocity of flow.
👉 Submerged broad crested weir (Cd = 0.83 to 0.85)
👉 Free broad crested weir ( Cd = 0.85 to 1)
👉 For ogee spillway ( Cd = 1.19 Cds), where Cds is the discharge coefficient for sharp crested weir.
👉 Cd value increases for ogee due to adhering Nappe
👉 Rehbock formula gives the expression for discharge over a rectangular suppressed weir.
Q = 2/3 (0.605 + 0.08 H/Z + 0.001/H) sqrt (2g). BH^1.5
👉 Francis found that due to end contraction the effective width of the nappe is reduced by o.1H.
Leff = (L - 0.1 nH)
👉 Cipolletti notch (or weir) is a trapezoidal notch which gives discharge equal to the discharge that would pass over a rectangular notch.
Q = 2/3 Cd sqrt(2g) LH^1.5
👉 Ventilation of Nappe: When there is no ventilation of nappe, discharge increases because the Nappe is pulled down due to negative pressure created in the zone below nappe.
👉 Let Q be the discharge in free Nappe then
For depressed Nappe Qd = (1.06-1.07) Q
For Adhering Nappe Qa = 1.25 Q
👉 Orifice is an opening in the tank and Mouthpiece is short length of tube
👉 Coefficient of resistance of Orifice (Cr) is defined as the ratio of Loss of KE through orifice to actual KE.
Cr = (1/Cv^2 -1)
where Cv is the coefficient of velocity.
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Monday, 26 July 2021
Target GATE & ESE 2022 (Fluid Mechanics)
Q.1 The range of coefficient of discharge for a venturimeter is
(a) 0.6-0.7 (b) 0.7-0.85 (c) 0.85-0.92 (d) 0.92-0.98
Q.2 A rotameter is used to measure:
(a) viscosity of fluids
(b) density of fluids
(c) flow rate of fluids
(d) rotational energy of a fluid
Q.3 Notch is a device used for measuring
(a) rate of flow through pipes
(b) rate of flow through a small channels
(c) flow velocity through a pipe line
(d) flow velocity through a small channel
Q.4 A cipolletti weir is:
(a) a rectangular weir of varying dimension
(b) a weir is designed for economical discharge
(c) a combination of a rectangular and triangular weir
(d) a trapezoidal weir whose side slopes are one horizontal to four vertical
Q.5 In a rectangular weir, the discharge varies as:
(a) H (b) H^0.5 (c) H^1.5 (d) H^2.5
Q.6 The sheet of water flowing through a notch or over a weir is known as
(a) Nappe (b) Crest (c) Height of weir/notch (d) Sill
Q.7 If the error in the measurement of head in a rectangular notch is 1% , then error in the measurement of discharge will be
(a) 1% (b) 1.5%
(c) 2% (d) 2.5%
Friday, 25 June 2021
Target GATE & ESE 2022 (Geotechnical Engineering-II)
Q.1 A and B are Skempton's pore pressure coefficients. For saturated normally consolidated soils
(a) A>1 and B>1 (b) A>1 and B<1
(c) A<1 and B>1 (d) A< 1 and B=1
Q.2 Consider the following statements:
1. Pore pressure parameter A is a constant for a soil.
2. The shear strength of soil is a function of the effective stress in the soil and not of the total stress in the soil.
Which of the statements given above is/are correct
(a) 1 only (b) 2 only
(c) Both 1 and 2 (d) Neither 1 nor 2
Q.3 Consider the following statements:
1. Brittle behavior of soils can be obtained when soil is heavily over-consolidated clay.
2. For a saturated soil Skempton's B-parameter is nearly equal to unity.
3. In UCS test minor principal stress equal to zero.
Which of these statements is/are correct
(a) 1,2 and 3 (b) 2 and 3 (c) 1 only (d) 3 only
Q.4 In an unconsolidated undrained triaxial test it is observed that an increase in cell pressure from 150 kPa to 250 kPa leads to a pore pressure increase of 80 kPa. It is further observed that an increase of 50 kPa in deviatoric stress results in an increase of 25 kPa in the pore pressure. The value of Skempton's pore pressure parameter B is:
(a) 0.5 (b) 0.625
(c) 0.80 (d) 1.0
Q.5 A clay soil sample is tested in a triaxial apparatus in consolidated drained conditions at a cell pressure of 100 kN/m^2. What will be the pore water pressure at a deviator stress of 40 kN/m^2?
(a) 0 (b) 20 kN/m^2
(c) 40 kN/m^2 (d) 60 kN/m^2
Thursday, 24 June 2021
Target GATE & ESE 2022 (Fluid Mechanics)
Do You Know ?
👉As per Bernoulli's equation:
Total head = P/Y + V^2/2g + z
Piezometric head = P/Y + z
Velocity head or kinetic head or dynamic head = v^2/2g
Stagnation head = P/Y + V^2/2g
👉Cavitation is the formation of vapour bubbles in a flowing liquid in the region where the pressure falls below vapour pressure and sudden collapsing of these vapour bubbles in a region of high pressure causes pitting.
👉 If time of closure (T) is less than equal to 2L/C → closure is sudden or instantaneous
👉 If time of closure (T) is greater than 2L/C → closure is gradual or slow.
👉 In case of sudden closure, when pipe is rigid
P = ρ CV
This formula is called Allievi Formula
👉Loss of head in both the cases, sudden expansion and sudden contraction happens due to formation of eddies, but the intensity is more in case of sudden expansion. Loss will be more in case of sudden expansion.
Another reason for more loss in case of sudden expansion is the deceleration of flow due to area expansion.
👉Surge tanks are used to absorb the increase in pressure due to water hammer phenomenon.
👉 Condition to satisfy Hardy Cross Method (Trial & Error Solution)
> The flow into any junction must equal the flow out of the junction (Continuity principle)
> The Darcy-weisbach equation must be satisfied for each pipe (hf = rQ^n)
> The algebric sum of head loss around any closed circuit will be zero when discharge distribution is correct.
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