Answer:
Explanation:
we have given E(t)=120 sin(12t)
R=5 ohm
L=0.2 H
ω=12 ( from expression of E)
[tex]X_L=0.2\times 12=2.4[/tex] ohm
[tex]X_C=\frac{1}{\omega \times C}=\frac{1}{12\times 0.043}=1.9379\ ohm[/tex]
[tex]Z=\sqrt{R^2+\left ( \omega L-\frac{1}{\omega C} \right )^2}[/tex]
[tex]Z=\sqrt{5^2+\left ( \2.4-1.9379 )^2}[/tex]
=5.021 ohm
so amplitude of current = [tex]\frac{v}{z}=\frac{120}{5.021}=23.89[/tex]
Fluid enters a device at 4 m/s and leaves it at 2 m/s. If there is no change in the PE of tihe flow, and there is no heat and (non-flow) work across boundaries of the device, what is the increase in specific enthalpyof the fluid (hg-hi) in kJ/kg? Assume steady state operation of the device.
Answer:
[tex]h_2-h_1=6\times 10^{-3}\frac{KJ}{Kg}[/tex]
Explanation:
Now from first law for open system
[tex]h_1+\dfrac{V_1^2}{2}+Q=h_2+\dfrac{V_2^2}{2}+w[/tex]
Here given Q=0 ,w=0
So [tex]h_1+\dfrac{V_1^2}{2}=h_2+\dfrac{V_2^2}{2}[/tex]
[tex]V_1=4 m/s,V_2=2 m/s[/tex]
[tex]h_1+\dfrac{4^2}{2000}=h_2+\dfrac{2^2}{2000}[/tex]
[tex]h_2-h_1=6\times 10^{-3}[/tex]
So increase in specific enthalpy
[tex]h_2-h_1=6\times 10^{-3}\frac{KJ}{Kg}[/tex]
What are the qualities required for a refrigerant? What is meant by the term "flash chamber?"
Answer:
A good quality refrigerant should be eco friendly.
Explanation:
A refrigerant is a substance that can extract and transfer heat from body to another body or medium.
The desirable qualities required for a refrigerant are :
1. A refrigerant should not deplete ozone layer.
2. A good quality refrigerant should have a low boiling point.
3. It should also have a low melting point.
4. Thermal conductivity of the refrigerant should be high for fast heat transfer.
5. It should have low specific heat.
6. It should have high latent heat.
7. It should have low vapour density.
8. Refrigerant should have high critical pressure and temperature.
9. It should have high enthalpy of vapourization for maximum heat absorption.
10. Refrigerants should not be toxic in nature and non flammable.
11. It should have high coefficient of performance for the working temperature range.
12. It should be easily available and cheap.
Flash Chamber :
A flash chamber in the refrigeration system is also know as the mixing chamber. It is normally used in multistage refrigeration system and is placed in between the expansion valve and the evaporator.
The flash chamber sends only the liquid refrigerant to the evaporator by seperating the liquid from the vapour refrigerant in order to increase the efficiency.
A flywheel made of Grade 30 cast iron (UTS = 217 MPa, UCS = 763 MPa, E = 100 GPa, density = 7100 Kg/m, Poisson's ratio = 0.26) has the following dimensions: ID = 150mm, OD = 250 mm and thickness = 37 mm. What is the rotational speed in rpm that would lead to the flywheel's fracture?
Answer:
N = 38546.82 rpm
Explanation:
[tex]D_{1}[/tex] = 150 mm
[tex]A_{1}= \frac{\pi }{4}\times 150^{2}[/tex]
= 17671.45 [tex]mm^{2}[/tex]
[tex]D_{2}[/tex] = 250 mm
[tex]A_{2}= \frac{\pi }{4}\times 250^{2}[/tex]
= 49087.78 [tex]mm^{2}[/tex]
The centrifugal force acting on the flywheel is fiven by
F = M ( [tex]R_{2}[/tex] - [tex]R_{1}[/tex] ) x [tex]w^{2}[/tex] ------------(1)
Here F = ( -UTS x [tex]A_{1}[/tex] + UCS x [tex]A_{2}[/tex] )
Since density, [tex]\rho = \frac{M}{V}[/tex]
[tex]\rho = \frac{M}{A\times t}[/tex]
[tex]M = \rho \times A\times t[/tex][tex]M = 7100 \times \frac{\pi }{4}\left ( D_{2}^{2}-D_{1}^{2} \right )\times t[/tex]
[tex]M = 7100 \times \frac{\pi }{4}\left ( 250^{2}-150^{2} \right )\times 37[/tex]
[tex]M = 8252963901[/tex]
∴ [tex]R_{2}[/tex] - [tex]R_{1}[/tex] = 50 mm
∴ F = [tex]763\times \frac{\pi }{4}\times 250^{2}-217\times \frac{\pi }{4}\times 150^{2}[/tex]
F = 33618968.38 N --------(2)
Now comparing (1) and (2)
[tex]33618968.38 = 8252963901\times 50\times \omega ^{2}[/tex]
∴ ω = 4036.61
We know
[tex]\omega = \frac{2\pi N}{60}[/tex]
[tex]4036.61 = \frac{2\pi N}{60}[/tex]
∴ N = 38546.82 rpm
Atmospheric air at 25 °C and 8 m/s flows over both surfaces of an isothermal (179C) flat plate that is 2.75m long. Determine the heat transfer rate per unit from the plate for 3 width different values of the critical Reynolds number: 100,000; 500,000; and 1,000,000
Answer:
Re=100,000⇒Q=275.25 [tex]\frac{W}{m^2}[/tex]
Re=500,000⇒Q=1,757.77[tex]\frac{W}{m^2}[/tex]
Re=1,000,000⇒Q=3060.36 [tex]\frac{W}{m^2}[/tex]
Explanation:
Given:
For air [tex]T_∞[/tex]=25°C ,V=8 m/s
For surface [tex]T_s[/tex]=179°C
L=2.75 m ,b=3 m
We know that for flat plate
[tex]Re<30\times10^5[/tex]⇒Laminar flow
[tex]Re>30\times10^5[/tex]⇒Turbulent flow
Take Re=100,000:
So this is case of laminar flow
[tex]Nu=0.664Re^{\frac{1}{2}}Pr^{\frac{1}{3}}[/tex]
From standard air property table at 25°C
Pr= is 0.71 ,K=26.24[tex]\times 10^{-3}[/tex]
So [tex]Nu=0.664\times 100,000^{\frac{1}{2}}\times 0.71^{\frac{1}{3}}[/tex]
Nu=187.32 ([tex]\dfrac{hL}{K_{air}}[/tex])
187.32=[tex]\dfrac{h\times2.75}{26.24\times 10^{-3}}[/tex]
⇒h=1.78[tex]\frac{W}{m^2-K}[/tex]
heat transfer rate =h[tex](T_∞-T_s)[/tex]
=275.25 [tex]\frac{W}{m^2}[/tex]
Take Re=500,000:
So this is case of turbulent flow
[tex]Nu=0.037Re^{\frac{4}{5}}Pr^{\frac{1}{3}}[/tex]
[tex]Nu=0.037\times 500,000^{\frac{4}{5}}\times 0.71^{\frac{1}{3}}[/tex]
Nu=1196.18 ⇒h=11.14 [tex]\frac{W}{m^2-K}[/tex]
heat transfer rate =h[tex](T_∞-T_s)[/tex]
=11.14(179-25)
= 1,757.77[tex]\frac{W}{m^2}[/tex]
Take Re=1,000,000:
So this is case of turbulent flow
[tex]Nu=0.037Re^{\frac{4}{5}}Pr^{\frac{1}{3}}[/tex]
[tex]Nu=0.037\times 1,000,000^{\frac{4}{5}}\times 0.71^{\frac{1}{3}}[/tex]
Nu=2082.6 ⇒h=19.87 [tex]\frac{W}{m^2-K}[/tex]
heat transfer rate =h[tex](T_∞-T_s)[/tex]
=19.87(179-25)
= 3060.36 [tex]\frac{W}{m^2}[/tex]
Explain very briefly the traditional casting and non-traditional casting process.
Answer:
traditional casting -- sand casting
non traditional casting - investment casting
Explanation:
Traditional casting is related to sand casting in which liquid is poured into mold cavity. once the poured material cool and solidify the casting is removed.
traditional casting is cheaper than non traditional casting . Mold use in traditional casting is very cheap .
non traditional casting include investment casting, die casting , wax casting. In this casting fix dimension is provided unlike sand casting.
________is the frequency that an engineered system fails, expressed for example, in failures per hour.
Answer:
Failure Rate
Explanation:
Failure rate is the frequency with which an engineered system or component fails, expressed for example in failures per hour.
It is often denoted by the Greek letter λ (lambda) and is important in reliability theory.
Failure rate is usually time dependent, and an intuitive corollary is that the rate changes over time versus the expected life cycle of a system
there are totally (___) slip system in an FCC metal.
Answer: 12
Explanation: In FCC metal lattice there are total four octahedral slip plane and six direction where each are common to two octahedral plane and so that gives total of three slip direction . So the total slip system is multiplication of the slip plane and the slip direction that is twelve.
Slip system=Slip plane×Slip direction
Slip system =4×3=12
Therefore there are total 12 slip system in the FCC metal lattice.
What is Euler's equation?
Answer:
[tex]e^{ix} = cosx + i sinx[/tex]
Explanation:
In mathematics, Euler's formula is an equation in complex analysis, that gives a relationship between an exponential factor and the trigonometric functions.
The Euler equation is:
[tex]e^{ix} = cosx + i sinx[/tex]
Here,
e - base of the natural logarithm
i - imaginary unit
x - argument given in radians
sin , cos - trigonometric functions sine and cosine respectively.
To select the center of a line what option must be selected? A. Ortho B. Dynamic input C. Object snap
Answer:
The correct answer is c. object snap
Explanation:
In Autocad, the object snap is defined as a drawing aid that is used together with other different commands to help to draw accurately. It also allows snapping onto a specific object location when there is a picking point. and thus, it helps to select the center of a line.
Heat transfer by is the fastest mode of heat transfer that requires no intervening medium. a)-conduction b)-convection c)-radiation d)-conduction and convection
Answer:
C. Radiation
Explanation:
Heat transfer through Conduction is a slow process and both Conduction and convection require material medium
Answer:
C radiation
Explanation:
Describe the importance of ferrite and austenite stabilizing elements in steels
Answer:
The importance of ferrite and austenite stabilizing elements in steels .
Explanation:
Alloying -
The process which improves the properties of the steel by changing the chemical composition of the steel via adding some elements .
The properties can be improved by - Stabilizing Austenite and Stabilizing Ferrite .
Stabilizing austenite -
The process by which temperature is increased , in which Austenite exists .
Elements with the same crystal structure as of the austenite ( FCC ) raises its A4 value i.e. the temperature of the formation of austenite from its liquid phase and reduces the value of A3 .
Hence, the elements are -
Cobalt , Nickel , Manganese , Copper.
The examples of the Austenitic steels are -
Hadfield Steel ( 13% Mn , 1.2% Cr , 1% C ) and Austenitic Stainless steel.
Stabilizing ferrite –
The process by which temperature is decreased , in which austenite exists .
Elements with the same crystal structure as of the ferrite (BCC - Cubic body centered ) lowers its A4 value i.e. the temperature of the formation of austenite from its liquid phase and increases the value of A3 .These elements have lower solubility of carbon in austenite, that lead to increase in the amount of carbides in the steel.
Hence, the elements are -
Aluminium , Silicon , Tungsten , Chromium , Molybdenum , Vanadium
The examples of the Ferritic steels are -
F-Cr alloys , transformer sheets steel ( 3% Si ).
A circuit has a source voltage of 15V and two resistors in series with a total resistance of 4000Ω .If RI has a potential drop of 9.375 V across it, what is the value of R2? (a) 2000Ω (b) 1500Ω (c) 1000Ω (d) 500Ω
Answer:
1500Ω
Explanation:
Given data
voltage = 15 V
total Resistance = 4000Ω
potential drop V = 9.375 V
To find out
R2
Solution
we know R1 +R2 = 4000Ω
So we use here Ohm's law to find out current I
current = voltage / total resistance
I = 15 / 4000 = 3.75 × [tex]10^{-3}[/tex] A
Now we apply Kirchhoffs Voltage Law for find out R2
R2 = ( 15 - V ) / current
R2 = ( 15 - 9.375 ) / 3.75 × [tex]10^{-3}[/tex]
R2 = 1500Ω
What are the major limitations of melt spinning method? a)-good for limited alloys and limited shapes b)-good for limited shapes, high cost c)-good for limited thickness and limited shapes d)-high cost, high energy consumption
Answer:d
Explanation:
Melt spinning is the economical process to manufacture synthetic fiber.
Major limitations of Melt spinning is
only suitable for thermoplastic fiberHigh heat inputRequire periodic maintenance of machinePrecise control of temperature is must.Although it is very efficient method as it does not create any environment Pollution
If a hoist lifts a 4500lb load 30ft in 15s, the power delivered to the load is a) 18.00hp b) 9000hp c) 16.36hp d) None of the above
Answer:
Explanation:
load = 4500lb lift height= 30 ft
time =15 s
velocity=[tex]\frac{30}{15}[/tex] ft/s
velocity=2 ft/s
power = force[tex]\times[/tex] velocity
power=[tex]{4500}\times2[/tex]
power= 9000 lb ft/s
1 hp= 550 lb ft/s
power= [tex]\frac{9000}{550} =16.36[/tex] hp
What is a truss? What separates a truss from a frame and other forms of rigid bodies?
Answer:
The application of force is the main difference between truss and frame.
Explanation:
Truss:
Truss is a collection of beams,which use to handle the tensile and compression loads . That collection of beams creates rigid structure.
The load on the truss will be acting always at the at the hinge. Truss is widely used in the construction areas.
Frame:
Like truss, it is also a combination of beams and used to handle the loads. The main difference between truss and frame is the application of load. In the frame load can apply at the any point of the member of frame along with hinge.
Truss are connected by pin joint and can not transfer moment ,on the other hand frames are connected by rigid joint like welding so frame can transfer moment.
Truss and frame both forms a rigid structure and is used in the construction areas.
Horizontal wind turbines have same design for offshore and on shore wind farms. a)-True b)- False
Answer: False
Explanation: Horizontal axis wind turbines are usually used for generation of the electric power on the off-shore. The generation of horizontal-axis wind turbine works well when it is installed away from the shore because it supports large sized wind turbines so that they can generate high amount of electricity.They are usually not preferred for the on-shore wind farms because they can have small sized wind turbines only.Therefore the statement given is false.
In an adiabatic process, the temperature of the system remains constant. a)- True b)- False
Answer:
A. True
Explanation:
Sam promises to pay Sandy $2,000 in four years and another $3,000 four years later for a loan of $2,000 from Sandy today. What is the interest rate that Sandy is getting? Assume interest is compounded monthly. A. 14.75% B. 16.72% C. 15.10% D. 18.08%
Answer:
the interest rate that Sandy is getting is (C.) 15.10%
Explanation:
Given data
in 4 year cash pay (p1) = $2000
in 8 year cash pay (p2) = $3000
time period (t1) = 4 years
time period (t2) = 8 years
loan value = $2000
To find out
interest rate
solution
first we know amount will be paid in first 4 year is
$2000 [tex](1+r/100)^{12t}[/tex]
$2000 [tex](1+r/100)^{48}[/tex] ...................1
now we calculate the next payment will paid after 4 year i.e.
$2000 [tex](1+r/100)^{12t}[/tex] - $2000
$2000 [tex](1+r/100)^{48}[/tex] - $2000 ..................2
after full time period of payment total amount will be paid by equation 1 and 2 i.e.
$3000 = $2000 [tex](1+r/100)^{48}[/tex] ×$2000 [tex](1+r/100)^{48}[/tex] - $2000
$3000 = $2000 ( [tex](1+r/100)^{48}[/tex] × [tex](1+r/100)^{48}[/tex] - 1 ) .....3
now we have solve [tex](1+r/100)^{48}[/tex] this eqution
so we consider [tex](1+r/100)^{48}[/tex] = A
so new equation will be by equation 3
$3000/$2000 = ( A - 1 ) × A
3/2 = A² - A
solve this equation we get 2A² - 2 A - 3 = 0 so A = 1.823
now we compute A again in [tex](1+r/100)^{48}[/tex] = A
[tex](1+r/100)^{48}[/tex] = 1.823
so rate (r) = 1.258 % / month
and rate yearly = 1.258 ×12
the interest rate that Sandy is getting yearly 15.10 %
In vibration analysis, can damping always be disregarded?
In vibration analysis, damping cannot always be disregarded. This is especially the case when the system is excited near the resonance frequency.
Explain why surface temperature increases when two bodies are rubbed against each other. What is the significance of temperature rise due to friction?
Answer:
The surface temperature increases when two bodies are rubbed against each other due to friction.
Explanation:
No object has a perfectly even surface. So, when two bodies with uneven surfaces are rubbed against each other, they experience friction.
Friction is a resistance experienced by the two bodies when they are moved against each other.
The friction between the two surfaces, converts the kinetic energy of the movement to the thermal energy.
Thus, resulting in rise in the surface temperature of the two bodies.
Therefore, when two bodies are rubbed against each other, the surface temperature increases due to friction.
What is refrigeration capacity and what is meant by a "ton" of refrigeration?
Answer:
1 ton refrigeration =3.517 kJ/s = 3.517 kW
Explanation:
Refrigeration capacity is defined at the measure of the effective cooling capacity of a refrigerator which is expressed in Btu per hour or in tons.
1 ton capacity is a unit of air conditioning and refrigeration which measure the capacity of air conditioning and refrigeration unit.
One ton is equal to removal of 3025kcal heat per hour
1 ton refrigeration = 200 Btu/min = 3.517 kJ/s = 3.517 kW = 4.713 HP
The manufacturing department of a factory is the only department that needs to be practicing Lean Manufacturing philosophy. a)- True b)- False
How are fluids distributed and transported in a fluid power system?
Answer and explanation :
Fluid distribution is a new technique to produce and to transmit power from one place to other its play a major role in power distribution it is a process of using fluid (any type of fluid as oil or water ) under pressure to generate to control or to transmit
fluid power system is divided into two types
Hydraulic fluid power systempneumatic fluid power system
If you know that the change in entropy of a cup of coffee where heat was added is 20 J/K, and that the temperature of the coffee is 250 K. what is the amount of heat added to the cup of coffee? a)-15 J b)-125J c)-600J d)-5000J d)-6000J
Answer:
5000J
Explanation:
Given in the question that
Heat added to the coffee cup is, ΔS = 20 J/K
The temperature of the coffee, T = 250 K
Now, using the formula for the entropy change
[tex]\bigtriangleup S=-\frac{\bigtriangleup H}{T}[/tex] ...........(1)
Where,
ΔS is the entropy change
ΔH is the enthalpy change
T is the temperature of the system
substituting the values in the equation (1)
we get
[tex]20=-\frac{\bigtriangleup H}{250}[/tex]
ΔH=250×20
ΔH=5000 J
A Carnot cooler operates with COP = 11, whose ambient temperature is 300K. Determine the temperature at which the refrigerator absorbs heat.
Answer:
275 Kelvin
Explanation:
Coefficient of Performance=11
[tex]T_H=\text {Absolute Temperature of high temperature reservoir=300 K}[/tex]
[tex]T_L=\text {Absolute Temperature of low temperature reservoir}[/tex]
[tex]\text {Coefficient of performance for carnot cooler}\\=\frac {T_L}{T_H-T_L}\\\Rightarrow 11=\frac{T_L}{300-T_L}\\\Rightarrow 11(300-T_L)=T_L\\\Rightarrow 3300-11T_L=T_L\\\Rightarrow 3300=T_L+11T_L\\\Rightarrow 3300=12T_L\\\Rightarrow T_L=\frac {3300}{12}\\\Rightarrow T_L=275\ K\\\Therefore \text{Temperature at which the refrigerator absorbs heat=275 Kelvin}[/tex]
Explain the Otto cycle of a 4 stroke engine.
Answer:
Otto cycle for 4 stroke engine:
Assumptions:
1.Air is a working fluid it will behave like ideal gas.
2.Mass of air is constant(close system)
3.All process is reversible process.
4.Specific heat of air does not depends on temperature.
4 stroke engine is an internal combustion engine.It works on 4 processes like intake ,compression,power and heat exhaust.To complete one cycle ,piston moves from top dead center to bottom dead center two times.
From the Otto cycle
Process 1-2 is isentropic compression.
Process 2-3 is heat addition.
Process 3-4 is isentropic expansion.
Process 4-1 is heat rejection.
Petrol engine works on Otto cycle.
Efficiency of cycle [tex]\eta[/tex]
[tex]\eta=\dfrac{W_{net}}{Q_{supply}}[/tex]
The Otto cycle is a four-step thermodynamic cycle used in four-stroke internal combustion engines to convert heat into work. It consists of the intake, compression, power, and exhaust strokes. The cycle helps in understanding engine efficiency and performance.
Explanation:The Otto cycle is a thermodynamic cycle that is used in four-stroke internal combustion engines. It consists of four processes: intake, compression, power, and exhaust.
The intake stroke is when the mixture of fuel and air is drawn into the combustion chamber. The compression stroke compresses the mixture adiabatically, increasing its temperature and pressure. During the power stroke, the mixture is ignited, creating a rapid increase in pressure that pushes the piston down. Finally, the exhaust stroke expels the burnt gases from the combustion chamber.
The Otto cycle is an idealized representation of the processes that occur in an engine and it describes the thermodynamic changes that are involved in converting heat into work. It helps in understanding the efficiency and performance of four-stroke engines.
Convert 0.025 in into mm.
Answer: 0.025 in = 0.065 mm
Explanation: To convert the value in inches to mm we have to multiply the inches by the conversion factor 25.4.
So, 0.025 × 25.4 = 0.065 mm (millimeter)
Conversion formula for calculation in (inch) into mm is:
Value in mm = Value in in × 25.4
One inch is equal to the 25.4 mm.Answer:
.025 inch = 0.635 mm
Explanation:
We know that 1 inch = 2.54 cm
also we know that 1 cm = 10 mm
Thus 1 inch = 2.54 x 10 mm
=> 1 inch = 25.4 mm
Hence 0.025 inch = 25.4 x .025 mm
Thus .025 inch = 0.635 mm
Thermosetting polymers are polymers that becomes soft and pliable when heated. ( True , False )
Answer:
Thermosetting polymers are polymers that becomes soft and pliable when heated is false
In an apartment the interior air temperature is 20°C and exterior air temperatures is 5°C. The wall has inner and outer surface temperatures of 16°C and 6°C, respectively. The inner and outer convection heat transfer coefficients are 5 and 20 W/m2.K, respectively. Calculate the heat flux from the interior air to the wall, from the wall to the exterior air, and from the wall to the interior air. Is the wall under steady-state conditions?
Answer:
20 W/m², 20 W/m², -20 W/m²
Yes, the wall is under steady-state conditions.
Explanation:
Air temperature in room = 20°C
Air temperature outside = 5°C
Wall inner temperature = 16°C
Wall outer temperature = 6°C
Inner heat transfer coefficient = 5 W/m²K
Outer heat transfer coefficient = 20 W/m²K
Heat flux = Concerned heat transfer coefficient × (Difference of the temperatures of the concerned bodies)
q = hΔT
Heat flux from the interior air to the wall = heat transfer coefficient of interior air × (Temperature difference between interior air and exterior wall)
⇒ Heat flux from the interior air to the wall = 5 (20-6) = 20 W/m²
Heat flux from the wall to the exterior air = heat transfer coefficient of exterior air × (Temperature difference between wall and exterior air)
⇒Heat flux from the wall to the exterior air = 20 (6-5) = 20 W/m²
Heat flux from the wall to the interior air = heat transfer coefficient of interior air × (Temperature difference between wall and interior air)
⇒Heat flux from the wall and interior air = 5 (16-20) = -20 W/m²
Here the magnitude of the heat flux are same so the wall is under steady-state conditions.
Describe how the diesel engine works.
Answer:
Diesel engine's working is based on internal combustion. Diesel engine can be categorized as two stroke diesel engines and 4 stroke diesel engines.
Let us look into the working of a 4 stroke diesel engine:
In a four stroke diesel engine the operation continues by rotating in cycle of 4 strokes or stages. In these 4 stages the piston moves up and down the crankcase twice or the crankshaft rotates twice. the four strokes are listed below:
1) Inlet: In this, the air mixture is made to enter through the inlet valve as the piston moves downwards.
2) Compression: Inlet valve is closed and the air mixture is compressed and the piston moves up. Fuel is injected into the heated air mixture through central injection valve and ignition takes place without the need of spark plug.
3) Expansion or Power: After ignition, mixture burns and due to expansion of gas, piston moves down, it drives the crankshaft to send power to the wheel.
4) Exhaust: This is the last stroke which results in the piston moving up to let out the exhaust gases
Moreover, in 2 stroke diesel engine, there is only one rotation of crankshaft and one stroke includes inlet and compression and the other includes expansion and exhaust