Answer:
(c) electronic
Explanation:
for pf, this is correct....Here is the sentence from the pf lesson
" The primary energy source for the controller within buildings is typically electric, pneumatic, or
electronic
."
If an electrical circuit can operate for 10.0 hours with a 2 Ah battery, what is the average current that the circuit demands?
a. 0.2 amperes.
b. 5 amperes.
c. 2 amperes.
d. 20 amperes.
Answer:
A
Explanation:
2/10 = 1/5 = 0.2
A cargo ship with LBP 134 m floats at 4.6 m and 4.2 m draught at FP and AP respectively. The centre of flotation is 2 m fwd of amidships and MCTC is 120 tonnes.M. Determine the position of 200 t of cargo to be loaded (from amidships) to ensure the ship floating in even keel condition after the loading completed.
Answer:
4.2019 mts , 4.598 mts
Explanation:
center of flotation = 2 m fwd.
MCTC = 120 tonnes
Determine the position of 200 t of cargo to be loaded
first step : determine the change trim = trimming moment / MCTC
= 134 * 1 / 120 = 0.11 mts
∴ бtf = 0.11 * ( 2/100 ) = 0.0022 mts ( given that the ship trims forward )
бtf = - 0.0022 mts
also ; бTa = 0.0019 mts ( + due to increase in draught )
determine the Final position
Ta = 4.2 ( draught at AP ) + бTa
= 4.2 + 0.0019
= 4.2019 mts
T[tex]_{f}[/tex] = 4.6 ( draught at Fp ) + бtf
= 4.6 + ( - 0.0022 ) = 4.598 mts
When you're running a test bench, you would like to include a printout to the screen to inform yourself on the status of the current simulation. Which command you could use to monitor specific variables or signals in a simulation every time one of the signals changes value?
Answer:
$Monitor
Explanation:
The command that would be used when running a test bench to monitor variables or signals ( i.e. changes in the values of specific variables and signa)
is the $Monitor command
This command is also used to monitor the varying values of signals during simulation.
Air enters a turbine with a stagnation pressure of 900 kPa and a stagnation temperature of 658K, and it is expanded to a stagnation pressure of 100 kPa. Assuming the expansion process is isentropic, determine the turbine power for a mass flow rate of 0.04 kg/s. What does the sign of the calculated power indicate
Answer:
12.332 KW
The positive sign indicates work done by the system ( Turbine )
Explanation:
Stagnation pressure( P1 ) = 900 kPa
Stagnation temperature ( T1 ) = 658K
Expanded stagnation pressure ( P2 ) = 100 kPa
Expansion process is Isentropic, also assume steady state condition
mass flow rate ( m ) = 0.04 kg/s
Calculate the Turbine power
Assuming a steady state condition
( p1 / p2 )^(r-1/r) = ( T1 / T2 )
= (900 / 100)^(1.4-1/1.4) = ( 658 / T2 )
= ( 9 )^0.285 = 658 / T2
∴ T2 = 351.22 K
Finally Turbine Power / power developed can be calculated as
Wt = mCp ( T1 - T2 )
= 0.04 * 1.005 ( 658 - 351.22 )
= 12.332 KW
The positive sign indicates work done by the system ( Turbine )
A clay sample was consolidated in a triaxial test under an all-around conning pressure of 15 lb/in.2. The sample was then loaded to failure in undrained condition by applying an additional axial stress of 22 lb/in.2. A pore water pressure sensor recorded an excess pore pressure of (Dud)f 5 29 lb/in.2 at failure. Determine the undrained and drained friction angles for the soil
Answer:
- the undrained friction angles for the soil is 25.02°
- the drained friction angles for the soil is 18.3°
Explanation:
Given the data in the question;
First we determine the major principle stress using the express;
σ₁ = σ₃ + (Δσ[tex]_d[/tex] )[tex]_f[/tex]
where σ₃ is the total minor principle stress at failure ( 15 lb/in² )
(Δσ[tex]_d[/tex] )[tex]_f[/tex] is the deviator stress ( -9 lb/in² )
so
σ₁ = 15 lb/in² + 22 lb/in²
σ₁ = 37 lb/in²
Now, we calculate the consolidated-undrained friction angle as follows;
∅ = sin⁻¹[ (σ₁ - σ₃ ) / ( σ₁ + σ₃ ) ]
∅ = sin⁻¹[ (37 - 15 ) / ( 37 + 15 ) ]
∅ = sin⁻¹[ 22 / 52 ]
∅ = sin⁻¹[ 0.423 ]
∅ = 25.02°
Therefore, the undrained friction angles for the soil is 25.02°
- The drained friction angles for the soil;
∅ = sin⁻¹[ (σ₁ - σ₃ ) / ( σ₁ + σ₃ - 2(Δσ[tex]_d[/tex] )[tex]_f[/tex] ) ]
so we substitute
∅ = sin⁻¹[ (37 - 15 ) / ( 37 + 15 - 2( -9 ) ]
∅ = sin⁻¹[ 22 / ( 37 + 15 + 18 ) ]
∅ = sin⁻¹[ 22 / 70 ]
∅ = sin⁻¹[ 0.314 ]
∅ = 18.3°
Therefore, drained friction angles for the soil is 18.3°
A square plate of titanium is 12cm along the top, 12cm on the right side, and 5mm thick. A normal tensile force of 15kN is applied to the top side of the plate. A normal tensile force of 20kN is applied to the right side of the plate. The elastic modulus, E, is 115 GPa for titanium. If the left and bottom edges of the plate are xed, calculate the normal strain and elongation of both the TOP and RIGHT side of the plate. Report your answer with proper units and signicant digits.
Answer:
For the Top Side
- Strain ε = 0.00021739
- Elongation is 0.00260868 cm
For The Right side
- Strain ε = 0.00021739
-Elongation is 0.00347826 cm
Explanation:
Given the data in the question;
Length of the squared titanium plate = 12 cm by 12 cm = 0.12 m by 0.12 m
Thickness = 5 mm = 0.005 m
Force to the Top F[tex]_t[/tex] = 15 kN = 15000 Newton
Force to the right F[tex]_r[/tex] = 20 kN = 20000 Newton
elastic modulus, E = 115 GPa = 115 × 10⁹ pascal
Now, For the Top Side;
- Strain = σ/E = F[tex]_t[/tex] / AE
we substitute
= 15000 / ( 0.12 × 0.005 × (115 × 10⁹) )
= 15000 / 69000000
Strain ε = 0.00021739
- Elongation
Δl = ε × l
we substitute
Δl = 0.00021739 × 12 cm
Δl = 0.00260868 cm
Hence, Elongation is 0.00260868 cm
For The Right side
- Strain = σ/E = F[tex]_r[/tex] / AE
we substitute
Strain = 20000 / ( 0.12 × 0.005 × (115 × 10⁹) )
= 20000 / 69000000
Strain ε = 0.000289855
- Elongation
Δl = ε × l
we substitute
Δl = 0.000289855× 12 cm
Δl = 0.00347826 cm
Hence, Elongation is 0.00347826 cm
In a residence, the control of a room's baseboard electric resistance heating system would be accomplished automatically using a?
A. wall-mounted pressure sensor.
B. duct-mounted thermostat.
C. wall-mounted humidity sensor.
D. wall-mounted thermostat.
Answer:
I think D is the correct answer.
Explanation:
hope its correct
A hemispherical shell with an external diameter of 500 mm and a thickness of 20 mm is going to be made by casting, located entirely in the upper part of the corresponding mold, with the maximum circle on the partition surface. If the density of the molten metal is 7.2 g / cm3 and the height of the pouring cavity above the partition surface is 300 mm, determine the metallostatic thrust that will be exerted on the upper mold at the end of casting.
Solution :
Given :
External diameter of the hemispherical shell, D = 500 mm
Thickness, t = 20 mm
Internal diameter, d = D - 2t
= 500 - 2(20)
= 460 mm
So, internal radius, r = 230 mm
= 0.23 m
Density of molten metal, ρ = [tex]$7.2 \ g/cm^3$[/tex]
= [tex]$7200 \ kg/m^3$[/tex]
The height of pouring cavity above parting surface is h = 300 mm
= 0.3 m
So, the metallostatic thrust on the upper mold at the end of casting is :
[tex]$F=\rho g A h$[/tex]
Area, A [tex]$=2 \pi r^2$[/tex]
[tex]$=2 \pi (0.23)^2$[/tex]
[tex]$=0.3324 \ m^2$[/tex]
[tex]$F=\rho g A h$[/tex]
[tex]$=7200 \times 9.81 \times 0.3324 \times 0.3$[/tex]
= 7043.42 N
what happens to the recievng end voltage as the load on a transmission line is increased if the load has a lagging power facotr
Answer:
The receiving end Voltage ( VR ) will reduce significantly
Explanation:
Determine what happens to the receiving end voltage
Given that ; Load on transmission line is increased and Load has a lagging power factor
Increase in load = Increase in reactive/real power drawn from the transmission line and this will cause an increase in the current drawn as well.
Vs = VR + j XL I
Vs = sending end voltage
VR = receiving end voltage
jXL I = voltage drop across reactance
The rotating and shifting of Vs to a new power angle ( lagging power factor ) without a change in magnitude will cause the value of the VR receiving end voltage to drop significantly
A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at 2300C by rejecting its waste heat to cooling water that enters the condenser at 180C at a rate of 0.25 kg/s and leaves at 260C. The refrigerant enters the condenser at 1.2 MPa and 650C and leaves at 420C. The inlet state of the compressor is 60 kPa and -340C and the compressor is estimated to gain a net heat of 450 W from the surroundings. Determine (a) the quality of the refrigerant at the evaporator inlet, (b) the mass flow rate of the refrigerant.
Correct question is;
A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at −30°C by rejecting its waste heat to cooling water that enters the condenser at 18°C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and −34°C and the compressor is estimated to gain a net heat of 450 W from the surroundings. Determine (a) the quality of the refrigerant at the evaporator inlet, (b) the mass flow rate of the refrigerant.
Answer:
A) Quality = 0.48
B) Mass flow rate; m' = 0.0455 kg/s
Explanation:
A) From the refrigerant R-144 table I attached,
At P=60kpa and interpolating at - 34°C,we obtain enthalpy;
h1 = 230.03 Kj/kg
Also at P= 1.2MPa which is 1200kpa and interpolating at 65°C,we obtain enthalpy ;
h2 = 295.16 Kj/Kg
Also at P= 1.2MPa which is 1200kpa and interpolating at 42°C,we obtain enthalpy ;
h3 = 111.23 Kj/Kg
h4 is equal to h3 and thus h4 = 111.23 Kj/kg
We want to find the refrigerant quality at the evaporation inlet which is state 4 and P= 60 Kpa.
Thus, from the table attached, we see that hf = 3.84 at that pressure and hg = 227.8
Now, to find the quality of the refrigerant, we'll use the formula,
x4 = (h4 - hg) /(hf - hg)
Where x4 is the quality of the refrigerant. Thus;
x4 = (111.23 - 3.84)/(227.8 - 3.84) = 0.48
B) The mass flow rate of the refrigerant can be determined by applying a 1st law energy balance across the condenser. Thus, the water properties can be obtained by using a saturated liquid at the given temperatures;
So using the first table in the image i attached; interpolating at 18°C; hw1 = hf = 75.54 kJ/kg
Also interpolating at 26°C; hw2 = hf = 109.01 kJ/kg
Now;
(m')(h2 − h3)= (m_w)(hw2 − hw1)
m' is mass flow rate
Making m' the subject, we get;
m' = [(m_w)(hw2 − hw1)]/(h2 − h3)
m' = [(0.25 kg/s)(109.01 − 75.54) kJ/kg] /(295.13 − 111.37) kJ/kg
m' = 8.3675/183.76
m' = 0.0455 kg/s
4. Which of the following is a mechanical property of a material? Conductivity o Strength Heat resistivity Weight
Answer:
The Mechanical Properties include Elasticity, Plasticity, Ductility, Malleability, Hardness, Toughness, Brittleness, Tenacity, Fatigue, Fatigue resistance, Impact Resistance property, Machineability, Strength, Strain Energy, Resilience, Proof Resilience, Modulus of Resilience, Creep, Rupture, and Modulus of Toughness.
Explain in your own words how standard form can be used to better communicate information in certain scientific or engineering contexts.
Answer:
Technical communication is a means to convey scientific, engineering, or other technical information.[1] Individuals in a variety of contexts and with varied professional credentials engage in technical communication. Some individuals are designated as technical communicators or technical writers. These individuals use a set of methods to research, document, and present technical processes or products. Technical communicators may put the information they capture into paper documents, web pages, computer-based training, digitally stored text, audio, video, and other media. The Society for Technical Communication defines the field as any form of communication that focuses on technical or specialized topics, communicates specifically by using technology or provides instructions on how to do something.[2][3] More succinctly, the Institute of Scientific and Technical Communicators defines technical communication as factual communication, usually about products and services.[4] The European Association for Technical Communication briefly defines technical communication as "the process of defining, creating and delivering information products for the safe, efficient and effective use of products (technical systems, software, services)".[5]
Whatever the definition of technical communication, the overarching goal of the practice is to create easily accessible information for a specific audience.[6]
The nominal live load for a four-story commercial building is 80 lb/ft2. The vertical load resisting system consists of flat plate floor slabs supported by a grid of columns spaced 25 ft in one plan direction and 20 ft in the other plan direction. What is the service live load for a first floor interior column, reduced according to ASCE-7 guidelines
Answer:
106 kips
Explanation:
Determine the service live load for a first floor interior column
following ASCE-7 guidelines
Area = 20 * 25 = 500 ft^2 which is > 400 ft^2
Nominal live load on every floor = 80 psf
Hence the reduced service live load ( L )
L = Lo [ 0.25 + 15 / √AI ] ------ ( 1 )
Lo = unreduced load
AT = Tributary area = 500 * number of floors = 2000 ft^2
AI ( influence area ) = AT * number of floors = 2000 * 4 = 8000 ft^2
Lo = 1.6 * 80 psf * 2000 ft^2 = 256 kips
Input values into equation 1 above
L = 106 kips
You will only have two attempts to answer this question correctly. Assuming you determine the required section modulus of a wide flange beam is 200 in3, determine the lightest beam possible that will satisfy this condition.
Answer:
W18 * 106
Explanation:
Section modulus of wide flange = 200 m^3
Determine the value of the lightest beam possible
The lightest beam possible that will satisfy the given condition will have a section modulus ≥ 200m^3 ( note: it will also be the nearest to 200 in^3 )
From Beam Table ; The Lightest beam with its section modulus( 204 in^3) > 200in^3 is W18 * 106
____ are intended to help provide the correct amount of ventilation and also help reduce cooling costs by allowing outside air to be introduced to the conditioned space when conditions are correct
Select the correct answer.
Which type of material functions as heat shields in space shuttles?
ОА. .
elastomers
OB.
metals
O c.
semiconductors
D.
plastics
E.
composites
C. Semiconductors.
They are made up of what is called a porous silicon material that is very light and extremely heat resistant.
Answer:
composites
Explanation:
_____ is the set of processes used to get members of an organization to work together to further the interests of the organization.
Answer:
organizational goals
Explanation:
The following true stresses produce the corresponding true plastic strains for a brass alloy: True Stress (psi) True Strain 48400 0.11 60400 0.19 What true stress is necessary to produce a true plastic strain of 0.26
Answer:
70,900
Explanation:
Given :
True stress (psi) _____ True strain (psi)
48400 ______________ 0.11
60400 ______________ 0.19
Using ratio simplification :
Let :
s = True stress ; t = true strain
s1 = 48400
s2 = 60400
t1 = 0.11
t2 = 0.19
True stress, s0 ; needed to produce a True plastic strain, tp = 0.26
(s0 - s1) / (s2 - s1) = (tp - t1) / (t2 - t1)
(s0 - 48400)/(60400 - 48400) = (0.26 - 0.11)/(0.19 - 0.11)
(s0 - 48400)/12000 = 0.15/0.08
Cross multiply :
0.08(s0 - 48400) = 0.15 * 12000
0.08s0 - 3872 = 1800
0.08s0 = 1800 + 3872
0.08s0 = 5672
s0 = 5762 / 0.08
s0 = 70,900
The true stress required to produce a true plastic strain of 0.26 is 70,900
IV. An annealed copper strip 9 inches wide and 2.2 inches thick, is rolled to its maximum possible draft in one pass. The following properties of annealed copper are given: strength coefficient is 90,000 psi; true strain at the onset of non-uniform deformation is 0.45; and, engineering strain at yield is 0.11. The coefficient of friction between strip and roll is 0.2. The roll radius is 14inches and the rolls rotate at 150 rpm. Calculate the roll-strip contact length. Calculate the absolute value of thetrue strain that the strip undergoes in this operation. Determine the average true stress of the strip in theroll gap. Calculate the roll force. Calculate the horsepower required.
Answer:
13.9357 horse power
Explanation:
Annealed copper
Given :
Width, b = 9 inches
Thickness, [tex]$h_0=2.2$[/tex] inches
K= 90,000 Psi
μ = 0.2, R = 14 inches, N = 150 rpm
For the maximum possible draft in one pass,
[tex]$\Delta h = H_0-h_f=\mu^2R$[/tex]
[tex]$=0.2^2 \times 14 = 0.56$[/tex] inches
[tex]$h_f = 2.2 - 0.56$[/tex]
= 1.64 inches
Roll strip contact length (L) = [tex]$\sqrt{R(h_0-h_f)}$[/tex]
[tex]$=\sqrt{14 \times 0.56}$[/tex]
= 2.8 inches
Absolute value of true strain, [tex]$\epsilon_T$[/tex]
[tex]$\epsilon_T=\ln \left(\frac{2.2}{1.64}\right) = 0.2937$[/tex]
Average true stress, [tex]$\overline{\gamma}=\frac{K\sum_f}{1+n}= 31305.56$[/tex] Psi
Roll force, [tex]$L \times b \times \overline{\gamma} = 2.8 \times 9 \times 31305.56$[/tex]
= 788,900 lb
For SI units,
Power = [tex]$\frac{2 \pi FLN}{60}$[/tex]
[tex]$=\frac{2 \pi 788900\times 2.8\times 150}{60\times 44.25\times 12}$[/tex]
= 10399.81168 W
Horse power = 13.9357
Which type of container traps the most heat a shoe box covered in aluminum foil plastic wrap or wax paper?
The container that traps the most heat is a shoebox covered in aluminum foil.
What is the use of aluminum foil?An aluminum foil is used for food storage, and to wrap items, such as meats, to minimize moisture loss while cooking.
Aluminum foil is also an excellent insulator. This is due to the fact that it reduces heat emission by reflecting it back.
Therefore, in a shoebox container, the aluminum foil helps to trap most heat better than a plastic wrap or wax paper.
Learn more about aluminum foil here:
https://brainly.com/question/277354
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In a residence, the control of a room's baseboard electric resistance heating system would be accomplished automatically using a?
A. wall-mounted pressure sensor.
B. duct-mounted thermostat.
C. wall-mounted humidity sensor.
D. wall-mounted thermostat.
Answer:
I think D is the correct answer
Explanation:
hope it is
What is the mass per unit area of an 7 inch by 10 inch lead sheet that weighs 192 gm. ____________g / cm2
Answer:
M/A = 0.425 g/cm²
Explanation:
Given the following data;
Mass = 192 grams
Dimensions = 7 * 10 inches.
To find the mass per unit area;
First of all, we would determine the area of the lead sheet;
Area = 7 * 10
Area = 70 in²
Conversion:
1 square inch = 6.452 square centimeters
70 inches = 70 * 6.452 = 451.64 square centimeters
Next, we find the mass per unit area;
M/A = 192/451.64
M/A = 0.425 g/cm²
HELP! It’s for an architecture class on PLATO
Select the correct answer.
Which association maintains the International Building Code?
A. NFPA
B. ICC
C. EPA
D. DOJ
Answer:
ICC
Explanation:
The International Building Code (IBC) is a model building code developed by the International Code Council (ICC). It has been adopted for use as a base code standard by most jurisdictions in the United States.
g Given a state of stress and , where is a positive constant with units of , what is the maximum allowable value of to avoid failure according to the Tresca/von Mises criterion if the material has yield strength .
Answer: Hello your question is poorly written attached below is the complete question
answer :
: max value to avoid failure = 59 MPa
; max value to avoid failure = 34.064 Mpa
Explanation:
Attached below is the detailed solution of the given problem
For Tresca criterion : max value to avoid failure = 59 MPa
For Von-Nissen criterion ; max value to avoid failure = 34.064 Mpa
The mass fraction of eutectoid cementite in a hypoeutectoid iron-carbon alloy (just below its eutectoid temperature) is 0.109. On the basis of this information, determine the composition of the alloy. If it is not possible to determine the composition from the information provided, enter 0.
Answer:
The composition of an alloy is 0.75%wt
Explanation:
Let alloy is a hypoeutectoid alloy.
So, we can apply lever rule which is shown below.
[tex]W_{a}=[/tex][tex]\frac{C_{0} -C_{a} }{C_{b}-C_{a} }[/tex]
We know that [tex]C_{a}=0.022[/tex] and [tex]C_{b}=6.7[/tex]
Given that [tex]W_{a}=0.109[/tex], we have to find [tex]C_{0}[/tex]
Thus,
[tex]0.109=\frac{C_{0}-0.022 }{6.7-0.022}[/tex]
Hence
[tex]C_{0}=0.75[/tex]%wt
A distillation column at 101 kPa is used to separate 350 kmol/h of a bubble point mixture of toluene and benzene into an overhead product with 3 mole % toluene and a bottoms product with 98 mole % toluene. The feed contains 0.45 mole fraction benzene. The overhead reflux occurs at saturation temperature (implies it is total condenser – if it was not, you would have a vapor liquid mixture or a partial condenser akin to a partial reboiler). VLE data for the mixture is given below. An average alpha can be found from the VLE data if solving analytically.
EQUILIBRIUM DATA IN MOLE- FRACTION BENZENE, 101 kPA
y 0.21 0.37 0.51 0.64 0.72 0.79 0.86 0.91 0.96 0.98
x 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0.95
Required:
a. What are the distillate and bottoms flow rates (D and B)?
b. What is the minimum reflux ratio, Rmin (corresponding to N= infinity)?
Answer:
A)
D = 158.42 kmol/h
B = 191.578 kmol/h
B) Rmin = 1.3095
Explanation:
a) Determine the distillate and bottoms flow rates ( D and B )
F = D + B ----- ( 1 )
Given data :
F = 350 kmol/j
Xf = 0.45 mole
yD ( distillate comp ) = 0.97
yB ( bottom comp ) = 0.02
back to equation 1
350(0.45) = 0.97 D + 0.02 B ----- ( 2 )
where; B = F - D
Equation 2 becomes
350( 0.45 ) = 0.97 D + 0.02 ( 350 - D ) ------ 3
solving equation 3
D = 158.42 kmol/h
resolving equation 2
B = 191.578 kmol/h
B) Determine the minimum reflux ratio Rmin
The minimum reflux ratio occurs when the enriching line meets the q line in the VLE curve
first we calculate the value of the enriching line
Y =( Rm / R + 1 m ) x + ( 0.97 / Rm + 1 )
q - line ; y = ( 9 / 9-1 ) x - xf/9-1
therefore ; x = 0.45
Finally Rmin
= (( 0.97 / (Rm + 1 )) = 0.42
0.42 ( Rm + 1 ) = 0.97
∴ Rmin = 1.3095
HOW TO CALCULATE MARGINAL RATE
Answer:
Divide the difference in tax by the amount of income from the investment, and you'll get the economic marginal tax rate from investing. Most people refer to marginal tax rates as being identical to tax brackets.
hope this helps
have a good day :)
Explanation:
A single fixed pulley is used to lift a load of 400N by the application of an effort of 480N in 10s through a vertical height of 5m. Determine the V.R, M.A and efficiency of the machine.
Answer:
(a) the velocity ratio of the machine (V.R) = 1
(b) The mechanical advantage of the machine (M.A) = 0.833
(c) The efficiency of the machine (E) = 83.3 %
Explanation:
Given;
load lifted by the pulley, L = 400 N
effort applied in lifting the, E = 480 N
distance moved by the effort, d = 5 m
(a) the velocity ratio of the machine (V.R);
since the effort applied moved downwards through a distance of d, the load will also move upwards through an equal distance 'd'.
V.R = distance moved by effort / distance moved by the load
V.R = 5/5 = 1
(b) The mechanical advantage of the machine (M.A);
M.A = L/E
M.A = 400 / 480
M.A = 0.833
(c) The efficiency of the machine (E);
[tex]E = \frac{M.A}{V.R} \times 100\%\\\\E = 0.833 \ \times \ 100\%\\\\ E = 83.3 \ \%[/tex]
Pie charts should have no more than eight segments. True or False?
Answer:
Explanation:
Pie charts generally should have no more than eight segments.
A full journal bearing has a shaft diameter of 3.000 in with a unilateral tolerance of -0.0004 in. The l/d ratio is unity. The bushing has a bore diameter of 3.003 in with a unilateral tolerance of 0.0012 in. The SAE 40 oil supply is in an axial-groove sump with a steady-state temperature of 140o F. The radial load is 675 lbf. Estimate the average film temperature, the minimum film thickness, the heat loss rate, and the lubricant side-flow rate for the minimum clearance assembly, if the journal speed is 10 rev/s.
Answer:
i) 154°F
ii) 0.0114 mm
iii) 0.075 btu/s
iv) 0.080 in^3/s
Explanation:
i)Determine the average film Temperature
( from Viscosity-temperature chart in US customary units for SAE10 )
at Temp = 154°F
absolute viscosity = 4.25 rev
and ΔT = 2 ( 154 - operating temp ) = 28°F
where : operating temp = 140°F as given in question
also from the chart applying Raimondi and Boyd boundary conditions
ΔT = 29°F hence we can pick 154°F as the average film temperature
ii) Calculate the minimum film thickness
Cmin = Bore diameter - Journal shaft diameter / 2
= 3.003 - 3 / 2 = 0.0015 in
Given that : h₀ / Cmin = 0.76
there h₀ = 0.0015 * 0.76 = 0.0114 mm
iii)Determine the heat loss rate
Also known as power loss ratio ( H ) = ( 2π*w*f*r*N ) / ( 778 *12 )
( 2π * 0.0132 * 675 * 1.5 * 10 ) / ( 9336 )
Heat loss rate = 0.075 btu/s
iv)Calculate lubricant side-flow rate for minimum clearance assembly
Side flow rate = 0.315 * Total volume flow rate
= 0.315 * ( 3.8 * 1.5 * 0.0015 * 10 * 3 )
= 0.080 in^3/s.