Answer:
check the explanation
Explanation:
1.
Thickness Loss =
Hence Rate of Corrosion = = 0.03 inches per year
2.
As the expected future life is 7 years,
40 carbon steel pipe has to be replaced every 3 years as given in the question,
Cost per unit length is the sum of material cost and installation cost.
Cost of 40 carbon steel = (5 dollars + 16.5 dollars) * 3 = 64.5 dollars
For 80 carbon steel pipe, first calculate the thickness loss,
The critical thickness is given to be 3mm, Hence change in thickness is 8.55-3 = 5.5mm
This 80 carbon steel pipe has to be replaced one more time
Hence, Cost per unit length is the sum of material cost and installation cost.
Cost of 80 carbon steel = (8.3 dollars + 16.5 dollars) * 2 = 49.6 dollars
The best is of stainless steel which does not undergo corrosion at all and thus it needs to be replaced only once throughout the plant operation. Its cost = 24.8 dollars + 16.5 dollars = 41.3 dollars
Hence, stainless steel is the recommended pipe to be used.
Answer:
Head loss is 1.64
Explanation:
Given data:
Length (L) = 200 m
Discharge (Q) = 0.16 m3/s
According to table of nominal pipe size , for schedule 80 , NPS 14, pipe has diameter (D)= 12.5 in or 31.8 cm 0.318 m
We know,
where, f = Darcy friction factor
V = flow velocity
g = acceleration due to gravity
We know, flow rate Q = A x V
solving for V
obtained Darcy friction factor
calculate Reynold number (Re) ,
where, = density of water
= Dynamic viscosity of water at 15 degree C = 0.001 Ns/m2
so reynold number is
= 6.4 x 10^5
For Schedule 80 PVC pipes , roughness (e) is 0.0015 mm
Relative roughness (e/D) = 0.0015 / 318 = 0.00005
from Moody diagram, for Re = 640000 and e/D = 0.00005 , Darcy friction factor , f = 0.0126
Therefore head loss is
HL = 1.64 m
Answer:
Car drivers and front seat passengers must wear a seat belt, unless they have a medical exemption certificate. Adults travelling in the rear of a car must also use seatbelts, if they're fitted. It's the responsibility of the adult passenger (not the driver) to make sure that they are using the seatbelt.
Answer:
a) 53 MPa, 14.87 degree
b) 60.5 MPa
Average shear = -7.5 MPa
Explanation:
Given
A = 45
B = -60
C = 30
a) stress P1 = (A+B)/2 + Sqrt ({(A-B)/2}^2 + C)
Substituting the given values, we get -
P1 = (45-60)/2 + Sqrt ({(45-(-60))/2}^2 + 30)
P1 = 53 MPa
Likewise P2 = (A+B)/2 - Sqrt ({(A-B)/2}^2 + C)
Substituting the given values, we get -
P1 = (45-60)/2 - Sqrt ({(45-(-60))/2}^2 + 30)
P1 = -68 MPa
Tan 2a = C/{(A-B)/2}
Tan 2a = 30/(45+60)/2
a = 14.87 degree
Principal stress
p1 = (45+60)/2 + (45-60)/2 cos 2a + 30 sin2a = 53 MPa
b) Shear stress in plane
Sqrt ({(45-(-60))/2}^2 + 30) = 60.5 MPa
Average = (45-(-60))/2 = -7.5 MPa
Explanation:
<u>Ohmic Behavior:</u>
If the current "I" produced in a conductor due to voltage "V" applied across it, is directly proportional to that voltage while the resistance of the conductor is same/constant, the material is said to be ohmic material or possessing ohmic behavior. If the resistance of a conductor doesn't remain the same due to heat, material property or any other reason, non-ohmic behavior will be observed.
<u>Thermal Expansion vs Ohmic/Non-ohmic property:</u>
For a linear conductor, thermal expansion (may be due to heat produced in result of current flow) increases length of the material due to which its resistance increases directly. Whenever the resistance increases during the flow of a current, the non-ohmic behavior arises.
R = ρL/A
where,
R=Resistance of conductor
ρ=Resistivity of material
L=length of conductor
A=Cross-sectional area of the conductor.
But,
usually this change in length and consequently change is resistance is very minor, so ignoring this change, the non-ohmic property of material will be minor too.
<u>Non-Ohmic Property:</u>
Current flows in a conductor due to flow of electrons in it. When these flowing electrons interacts with other particles (electron or atoms' nucleus) heat is produced. Due to this heat, atomic particles vibrates with more speed resulting in more hindrance/resistance in the flow of electron i.e. Resistance of material is now increased, so this will result in Non-ohmic behavior because now for the same value of applied voltage V, the flow of electron (Current) will be lesser. This will result in deviation from straight line graph as well (picture is attached)