Answer:
Use cases are known to be a set of instruction or processes between a User/Actor with the system to produce a desired input.
With the aid of a diagram, the set of use cases that are carried out in this ATM are given below:
Insert PIN
(1)Perform required transaction
(2)Withdrawal
(3)Deposit
(4)Transfer
(5)Change PIN
(6)Exit
Note: Kindly find an attached diagram of the Use case as part of the solution to process carried out at the ATM
Sources: The diagram of the Use case for ATM was researched and taken from Quizlet.
Explanation:
Solution
Use cases are normally a set of instruction or processes between a User/Actor with the system to produce a desired input.
A use case diagram or image is a graphical representation of all the use case or processes that connects or interact with the system
The use case diagram is a part of Unified Modelling Language also called the UML.
The set of use cases that are carried out in this ATM use case diagram to know the requirements of the ATM is shown below:
Insert PINPerform required transactionWithdrawalDepositTransferChange PINExitNow both the customer/client and Bank are seen as Actors.
Actors are the ones or people that interface with the system.
The ATM is often used to withdraw money and it also have some requirement.
What are the use cases explain the use cases for ATM withdrawal?Some of the use-cases that could serve as a basis for understanding the requirements for an ATM system are;
Customer (actor) often uses bank ATM to know or see the Balances of his/her bank accounts. They use it also to Deposit Funds and Withdraw Cash.
They can also use it to Transfer Funds (use cases). ATM Technician are known to give a form of Maintenance and Repairs. All these used cases is one that involve Bank as the actor when it is liked to customer transactions or to the ATM servicing.
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A four-cylinder, four-stroke internal combustion engine has a bore of 3.7 in. and a stroke of 3.4 in. The clearance volume is 16% of the cylinder volume at bottom dead center and the crankshaft rotates at 2400 RPM. The processes within each cylinder are modeled as an air-standard Otto cycle with a pressure of 14.5 lbf/in. 2 and a temperature of 60 8 F at the beginning of compression. The maximum temperature in the cycle is 5200 8 R.
Based on this model,
1- Write possible Assumptions no less than three assumptions
2- Draw clear schematic for this problem
3- Determine possible Assumptions no less than three assumptions
4- Draw clear schematic for this problem.
5- calculate the net work per cycle, in Btu, and the power developed by the engine, in horsepower.
Answer:
1) The three possible assumptions are
a) All processes are reversible internally
b) Air, which is the working fluid circulates continuously in a closed loop
cycle
c) The process of combustion is depicted as a heat addition process
2) The diagrams are attached
5) The net work per cycle is 845.88 kJ/kg
The power developed in horsepower ≈ 45374 hP
Explanation:
1) The three possible assumptions are
a) All processes are reversible internally
b) Air, which is the working fluid circulates continuously in a closed loop
cycle
c) The process of combustion is depicted as a heat addition process
2) The diagrams are attached
5) The dimension of the cylinder bore diameter = 3.7 in. = 0.09398 m
Stroke length = 3.4 in. = 0.08636 m.
The volume of the cylinder v₁= 0.08636 ×(0.09398²)/4 = 5.99×10⁻⁴ m³
The clearance volume = 16% of cylinder volume = 0.16×5.99×10⁻⁴ m³
The clearance volume, v₂ = 9.59 × 10⁻⁵ m³
p₁ = 14.5 lbf/in.² = 99973.981 Pa
T₁ = 60 F = 288.706 K
[tex]\dfrac{T_{2}}{T_{1}} = \left (\dfrac{v_{1}}{v_{2}} \right )^{K-1}[/tex]
Otto cycle T-S diagram
T₂ = 288.706*[tex]6.25^{0.393}[/tex] = 592.984 K
The maximum temperature = T₃ = 5200 R = 2888.89 K
[tex]\dfrac{T_{3}}{T_{4}} = \left (\dfrac{v_{4}}{v_{3}} \right )^{K-1}[/tex]
T₄ = 2888.89 / [tex]6.25^{0.393}[/tex] = 1406.5 K
Work done, W = [tex]c_v[/tex]×(T₃ - T₂) - [tex]c_v[/tex]×(T₄ - T₁)
0.718×(2888.89 - 592.984) - 0.718×(1406.5 - 288.706) = 845.88 kJ/kg
The power developed in an Otto cycle = W×Cycle per second
= 845.88 × 2400 / 60 = 33,835.377 kW = 45373.99 ≈ 45374 hP.
If the contact surface between the 20-kg block and the ground is smooth, determine the power of force F when t = 4 s. Initially, the block is at rest
Answer:
115.2 W
Explanation:
The computation is shown below:
As we know that
Power = F . v
[tex]F_H = F cos \theta[/tex]
[tex]F_H = 30 \frac{4}{5}[/tex]
[tex]F_H = 24N[/tex]
Now we solve for V
[tex]V = V_0 + at[/tex] a = 24N ÷ 20Kg
But V_0 = 0 a = 1.2 m/s^2
F_H = ma V = 0 + (1.2) (4)
a = F_H ÷ m V = 4.8 m/s
Therefore
Power = F_Hv
= (24) (4.8)
= 115.2 W
By applying the above formuals we can get the power
Methane gas is 304 C with 4.5 tons of mass flow per hour to an uninsulated horizontal pipe with a diameter of 25 cm. It enters at a temperature and exits at 284 C. The pipe is smooth and its length is 10 m. temperature is 25 ° C. Since the smear coefficient of the pipe surface is given as 0.8; a-) Indoor and outdoor convection coefficients (W / m2K), b-) Heat loss from the pipe to the environment (W), c-) The surface temperature of the pipe (C), d-) Calculate the required fan control (W) and interpret the results.
Answer:
a) [tex]h_c = 0.1599 W/m^2-K[/tex]
b) [tex]H_{loss} = 5.02 W[/tex]
c) [tex]T_s = 302 K[/tex]
d) [tex]\dot{Q} = 25.125 W[/tex]
Explanation:
Non horizontal pipe diameter, d = 25 cm = 0.25 m
Radius, r = 0.25/2 = 0.125 m
Entry temperature, T₁ = 304 + 273 = 577 K
Exit temperature, T₂ = 284 + 273 = 557 K
Ambient temperature, [tex]T_a = 25^0 C = 298 K[/tex]
Pipe length, L = 10 m
Area, A = 2πrL
A = 2π * 0.125 * 10
A = 7.855 m²
Mass flow rate,
[tex]\dot{ m} = 4.5 tons/hr\\\dot{m} = \frac{4.5*1000}{3600} = 1.25 kg/sec[/tex]
Rate of heat transfer,
[tex]\dot{Q} = \dot{m} c_p ( T_1 - T_2)\\\dot{Q} = 1.25 * 1.005 * (577 - 557)\\\dot{Q} = 25.125 W[/tex]
a) To calculate the convection coefficient relationship for heat transfer by convection:
[tex]\dot{Q} = h_c A (T_1 - T_2)\\25.125 = h_c * 7.855 * (577 - 557)\\h_c = 0.1599 W/m^2 - K[/tex]
Note that we cannot calculate the heat loss by the pipe to the environment without first calculating the surface temperature of the pipe.
c) The surface temperature of the pipe:
Smear coefficient of the pipe, [tex]k_c = 0.8[/tex]
[tex]\dot{Q} = k_c A (T_s - T_a)\\25.125 = 0.8 * 7.855 * (T_s - 298)\\T_s = 302 K[/tex]
b) Heat loss from the pipe to the environment:
[tex]H_{loss} = h_c A(T_s - T_a)\\H_{loss} = 0.1599 * 7.855( 302 - 298)\\H_{loss} = 5.02 W[/tex]
d) The required fan control power is 25.125 W as calculated earlier above
The effectiveness of a heat exchanger is defined as the ratio of the maximum possible heat transfer rate to the actual heat transfer rate.
a. True
b. False
Answer:
False
Explanation:
Because
The effectiveness (ϵ) of a heat exchanger is defined as the ratio of the actual heat transfer to the maximum possible heat transfer.
Anytime scaffolds are assembled or __________, a competent person must oversee the operation.
a. Drawn
b. Disassembled
c. Thought
d. Made
When scaffolds are now being construct or deconstruct, a competent person must supervise the work and train everybody who'll be assisting, and the further discussion can be defined as follows:
The competent person is also responsible for proposing whether fall protection is required for each scaffold erected. In constructing a scaffold, there are specific criteria for the ground the scaffold is constructed. On the products and components used to build the scaffold, its height in relation to the foundation. It's platform's design, and whether or not high efficiency is needed to supervise the installation.Therefore, the final answer is "Option B".
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Calculate the resistance using Voltage and current, again using voltage and power, again using current and power, and again using R1 and R2 recording the calculations for Run 3 rows 41-56
Answer:
R = V / I , R = V² / P, R = P / I²
Explanation:
For this exercise let's use ohm's law
V = I R
R = V / I
Electric power is defined by
P = V I
ohm's law
I = V / R
we substitute
P = V (V / R)
P = V² / R
R = V² / P
the third way of calculation
P = (i R) I
P = R I²
R = P / I²
A steam turbine receives 8 kg/s of steam at 9 MPa, 650 C and 60 m/s (pressure, temperature and velocity). It discharges liquid-vapor mixture with a quality of 0.94 at a pressure of 325 kPa and a velocity of 15 m/s. In addition, there is heat transfer from the turbine to the surroundings for 560 kW. Find the power produced by the turbine and express it in kW?
Answer:
The power produced by the turbine is 23309.1856 kW
Explanation:
h₁ = 3755.39
s₁ = 7.0955
s₂ = sf + x₂sfg =
Interpolating fot the pressure at 3.25 bar gives;
570.935 +(3.25 - 3.2)/(3.3 - 3.2)*(575.500 - 570.935) = 573.2175
2156.92 +(3.25 - 3.2)/(3.3 - 3.2)*(2153.77- 2156.92) = 2155.345
h₂ = 573.2175 + 0.94*2155.345 = 2599.2418 kJ/kg
Power output of the turbine formula =
[tex]Q - \dot{W } = \dot{m}\left [ \left (h_{2}-h_{1} \right )+\dfrac{v_{2}^{2}- v_{1}^{2}}{2} + g(z_{2}-z_{1})\right ][/tex]
Which gives;
[tex]560 - \dot{W } = 8\left [ \left (2599.2418-3755.39 \right )+\dfrac{15^{2}- 60^{2}}{2} \right ][/tex]
= -8*((2599.2418 - 3755.39)+(15^2 - 60^2)/2 ) = -22749.1856
[tex]- \dot{W }[/tex] = -22749.1856 - 560 = -23309.1856 kJ
[tex]\dot{W }[/tex] = 23309.1856 kJ
Power produced by the turbine = Work done per second = 23309.1856 kW.
A 10-ft-long simply supported laminated wood beam consists of eight 1.5-in. by 6-in. planks glued together to form a section 6 in. wide by 12 in. deep. The beam carries a 9-kip concentrated load at midspan. Which point has the largest Q value at section a–a?
Answer:
point B where [tex]Q_B = 101.25 \ in^3[/tex] has the largest Q value at section a–a
Explanation:
The missing diagram that is suppose to be attached to this question can be found in the attached file below.
So from the given information ;we are to determine the point that has the largest Q value at section a–a
In order to do that; we will work hand in hand with the image attached below.
From the image attached ; we will realize that there are 8 blocks aligned on top on another in the R.H.S of the image with the total of 12 in; meaning that each block contains 1.5 in each.
We also have block partitioned into different point segments . i,e A,B,C, D
For point A ;
Let Q be the moment of the Area A;
SO ; [tex]Q_A = Area \times y_1[/tex]
where ;
[tex]y_1 = (6 - \dfrac{1.5}{2})[/tex]
[tex]y_1 = (6- 0.75)[/tex]
[tex]y_1 = 5.25 \ in[/tex]
[tex]Q_A =(L \times B) \times y_1[/tex]
[tex]Q_A =(6 \times 1.5) \times 5.25[/tex]
[tex]Q_A =47.25 \ in^3[/tex]
For point B ;
Let Q be the moment of the Area B;
SO ; [tex]Q_B = Area \times y_2[/tex]
where ;
[tex]y_2 = (6 - \dfrac{1.5 \times 3}{2})[/tex]
[tex]y_2= (6 - \dfrac{4.5}{2}})[/tex]
[tex]y_2 = (6 -2.25})[/tex]
[tex]y_2 = 3.75 \ in[/tex]
[tex]Q_B =(L \times B) \times y_1[/tex]
[tex]Q_B=(6 \times 4.5) \times 3.75[/tex]
[tex]Q_B = 101.25 \ in^3[/tex]
For point C ;
Let Q be the moment of the Area C;
SO ; [tex]Q_C = Area \times y_3[/tex]
where ;
[tex]y_3 = (6 - \dfrac{1.5 \times 2}{2})[/tex]
[tex]y_3 = (6 - 1.5})[/tex]
[tex]y_3= 4.5 \ in[/tex]
[tex]Q_C =(L \times B) \times y_1[/tex]
[tex]Q_C =(6 \times 3) \times 4.5[/tex]
[tex]Q_C=81 \ in^3[/tex]
For point D ;
Let Q be the moment of the Area D;
SO ; [tex]Q_D = Area \times y_4[/tex]
since there is no area about point D
Area = 0
[tex]Q_D =0 \times y_4[/tex]
[tex]Q_D = 0[/tex]
Thus; from the foregoing ; point B where [tex]Q_B = 101.25 \ in^3[/tex] has the largest Q value at section a–a
Which of the following are the main psychological domains?
Answer:
Domain 1: Biological (includes neuroscience, consciousness, and sensation) Domain 2: Cognitive (includes the study of perception, cognition, memory, and intelligence) Domain 3: Development (includes learning and conditioning, lifespan development, and language) i hope this helps you.
If there are 16 signal combinations (states) and a baud rate (number of signals/second) of 8000/second, how many bps could I send
Answer:
32000 bits/seconds
Explanation:
Given that :
there are 16 signal combinations (states) = 2⁴
bits n = 4
and a baud rate (number of signals/second) = 8000/second
Therefore; the number of bits per seconds can be calculated as follows:
Number of bits per seconds = bits n × number of signal per seconds
Number of bits per seconds = 4 × 8000/second
Number of bits per seconds = 32000 bits/seconds
If the contact surface between the 20-kg block and the ground is smooth, determine the power of force F when t = 4 s. Initially, the block is at rest
Answer:
The power of force F is 115.2 W
Explanation:
Use following formula
Power = F x V
[tex]F_{H}[/tex] = F cos0
[tex]F_{H}[/tex] = (30) x 4/5
[tex]F_{H}[/tex] = 24N
Now Calculate V using following formula
V = [tex]V_{0}[/tex] + at
[tex]V_{0}[/tex] = 0
a = [tex]F_{H}[/tex] / m
a = 24N / 20 kg
a = 1.2m / [tex]S^{2}[/tex]
no place value in the formula of V
V = 0 + (1.2)(4)
V = 4.8 m/s
So,
Power = [tex]F_{H}[/tex] x V
Power = 24 x 4.8
Power = 115.2 W
Select True/False for each of the following statements regarding aluminum / aluminum alloys: (a) Aluminum alloys are generally not viable as lightweight structural materials in humid environments because they are highly susceptible to corrosion by water vapor. (b) Aluminum alloys are generally superior to pure aluminum, in terms of yield strength, because their microstructures often contain precipitate phases that strain the lattice, thereby hardening the alloy relative to pure aluminum. (c) Aluminum is not very workable at high temperatures in air, in terms of extrusion and rolling, because a non-protective oxide grows and consumes the metal, converting it to a hard and brittle ceramic. (d) Compared to most other metals, like steel, pure aluminum is very resistant to creep deformation. (e) The relatively low melting point of aluminum is often considered a significant limitation for high-temperature structural applications.
Explanation:
(a) Aluminum alloys are generally not viable as lightweight structural materials in humid environments because they are highly susceptible to corrosion by water vapor.
False, aluminium is not susceptible to any corrosion by the presence of water vapor.
(b) Aluminum alloys are generally superior to pure aluminum, in terms of yield strength, because their micro structures often contain precipitate phases that strain the lattice, thereby hardening the alloy relative to pure aluminum.
True.
(c) Aluminum is not very workable at high temperatures in air, in terms of extrusion and rolling, because a non-protective oxide grows and consumes the metal, converting it to a hard and brittle ceramic.
False, aluminium is stable at high temperatures and does not oxidizes.
(d) Compared to most other metals, like steel, pure aluminum is very resistant to creep deformation.
False,pure aluminium is not resistant to the creep deformation.
(e) The relatively low melting point of aluminum is often considered a significant limitation for high-temperature structural applications.
False.
In this exercise, we have to analyze the statements that deal with aluminum and its properties, thus classifying it as true or false:
A) False
B) True
C) False
D) False
E) True
Analyzing the statements we can classify them as:
(a) For this statement we can say that it is False, aluminium is not susceptible to any corrosion by the presence of water vapor.
(b) For this statement we can say that it is True.
(c) For this statement we can say that it is False, aluminium is stable at high temperatures and does not oxidizes.
(d) For this statement we can say that it is False, pure aluminium is not resistant to the creep deformation.
(e) For this statement we can say that it is True.
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potential difference is the work done in moving a unit positive charge from one point to another in an electric field. State True/False.
Answer:
True
Explanation:
Because the Electric Magnetic Field is the work done per unit charge where other forms of energy is tranferred to electrical energy
A spring (70 N/m ) has an equilibrium length of 1.00 m. The spring is compressed to a length of 0.50 m and a mass of 2.2 kg is placed at its free end on a frictionless slope which makes an angle of 41 ∘ with respect to the horizontal. The spring is then released.
Required:
a. If the mass is not attached to the spring, how far up the slope from the compressed point will the mass move before coming to rest?
b. If the mass is attached to the spring, how far up the slope from the compressed point will the mass move before coming to rest?
c. Now the incline has a coefficient of kinetic friction μk. If the block, attached to the spring, is observed to stop just as it reaches the spring's equilibrium position, what is the coefficient of friction μk?
Answer:
a) The mass moves a distance of 0.625 m up the slope before coming to rest
b) The distance moved by the mass when it is connected to the spring is 0.6 m
c) [tex]\mu = 0.206[/tex]
Explanation:
Spring constant, k = 70 N/m
Compression, x = 0.50 m
Mass placed at the free end, m = 2.2 kg
angle, θ = 41°
Potential Energy stored in the spring, [tex]PE= 0.5 kx^2[/tex]
[tex]PE = 0.5 * 70 * 0.5^2\\PE = 8.75 J[/tex]
According to the principle of energy conservation
PE = mgh
8.75 = 2.2 * 9.8 * h
h = 0.41
If the mass moves a distance d from the spring
sin 41 = h/d
sin 41 = 0.41/d
d = 0.41/(sin 41)
d = 0.625 m
The mass moves a distance of 0.625 m up the slope before coming to rest
b) If the mass is attached to the spring
According to energy conservation principle:
Initial PE of spring = Final PE of spring + PE of block
[tex]0.5kx_1^2 = 0.5kx_2^2 + mgh\\x_2 = d - x_1 = d - 0.5\\h = d sin 41\\0.5*70*0.5^2 = 0.5*70*(d-0.5)^2 + 2.2*9.8*d*sin41\\8.75 = 35(d^2 - d + 0.25) + 14.15d\\8.75 = 35d^2 - 35d + 8.75 + 14.15d\\35d^2 = 20.85d\\d = 0.6 m[/tex]
The distance moved by the mass when it is connected to the spring is 0.6 m
3) The spring potential is converted to increased PE and work within the system.
mgh = Fd + 0.5kx²...........(1)
d = x , h = dsinθ
kinetic friction force , F = μmgcosθ
mgdsinθ + μmg(cosθ)d = 0.5kd²
mgsinθ + μmgcosθ = 0.5kd
sinθ + μcosθ = kd/(2mg)
[tex]\mu = \frac{\frac{kd}{2mg} - sin\theta}{cos\theta} \\\\\mu = \frac{\frac{70*0.5}{2*2.2*9.8} - sin41}{cos41} \\\\\mu = 0.206[/tex]
Answer:
A) l = 0.619m
B) l = 0.596m
C) μ = 0.314
Explanation:
The data given is:
k = 70 N/m
x = 0.5 m
m = 2.2 kg
θ = 41°
(FIGURES FOR EACH PART ARE ATTACHED AT THE BOTTOM. CONSULT THEM FOR BETTER UNDERSTANDING)
Part A
Gain in Gravitational Potential Energy = Loss in Elastic Potential Energy
mgh = (1/2)kx²
(2.2)(9.8)h = (1/2)(70)(0.5)²
h = 0.406 m
sinθ = h/l
l = h / sinθ
l = 0.406/sin41
l = 0.619m
Part B
Loss in Elastic Potential Energy in compressed spring = Gain in Gravitational Potential Energy + Gain in Elastic Potential Energy in stretched spring
(1/2)kx² = mgh + (1/2)k(l - 0.5)²
(1/2)(70)(0.5)² = (2.2)(9.8)(l·sin41)) + (1/2)(70)(l² - l + 1/4)
8.75 = 14.15(l) + 35(l²) - 35(l) + 8.75
35(l²) -20.85(l) = 0
l = 0.596m
Part C
Loss in Elastic Potential Energy = Gain in Gravitational Potential Energy + Work done against friction
(1/2)kx² = mgh + Fd
(1/2)kx² = mg(dsinθ) + μRd
(1/2)kx² = mg(dsinθ) + μ(mg · cosθ)d
(1/2)kx² = mgd (sinθ + μ(cosθ))
(1/2)(70)(0.5)² = (2)(9.8)(0.5) (sin41 + μcos41)
8.75 = 6.43 + 7.4μ
μ = 0.314
There are two piston-cylinder systems that each contain 1 kg of an idea gas at a pressure of 300 kPa and temperature of 350 K. The two systems then undergo two different processes:
System 1 undergoes process 1 as follows:
Isobaric heating to 500 K, then compressed to a pressure of 500 kPa and a temperature of 600 K.
System 2 undergoes process 2 as follows:
Directly compressed in one step to a pressure 500 kPa and a temperature of 600 K
We "measure" the entropy of each system before and after the process. Which system had the biggest entropy change?
a. System 1
b. System 2
c. Entropy change is the same for both systems
Answer:
Entropy change is same for both systems because entropy is a state function i.e., it doesn't depend on the path by which the system arrived at it's present state (500 kPa, 600 K) from initial state (300 kPa, 350 K) .
Explanation:
Question 1 The first choice for how to reduce or eliminate a hazard is: a) Engineering controls b) Workplace controls c) Personal protective equipment d) Administrative controls
Answer:
a) Engineering controls.
Explanation:
Hazard can be defined as any agent or source that has the potential to constitute danger and cause harm, damage or adverse bodily injuries, health effects on a vulnerable individual, property or group of people.
Generally, can be classified into various categories such as mechanical, biological, chemical, physical, psychosocial and ergonomic hazard. These hazards are either human induced or natural.
Some examples of hazard are radiation, fire, flood, chemicals, drought, vapor or steam, exposed live wire, dust particles, electrical circuits and equipments etc.
The first choice for how to reduce or eliminate a hazard is engineering controls. Engineering controls of hazards involves the process of protecting, shielding or guarding individuals by eliminating the agent of hazards or through the use of barriers between the hazard and the vulnerable individual or group of people.
Basically, engineering controls when properly designed, maintained and used effectively would help to mitigate hazards and keep the work environment relatively safe for workers.
Examples of engineering controls are;
1. Ventilation systems.
2. Machine or equipment guards.
3. Radiation shields.
4. Safety interlocks.
5. Sound dampening equipments.
Find the heat flow from the composite wall as shown in figure. Assume one dimensional flow KA=150 W/m°C , KB=25 W/m°C, KC=60 W/m°C , KD=60 W/m°C
Answer:
The heat flow from the composite wall is 1283.263 watts.
Explanation:
The conductive heat flow through a material, measured in watts, is represented by the following expression:
[tex]\dot Q = \frac{\Delta T}{R_{T}}[/tex]
Where:
[tex]R_{T}[/tex] - Equivalent thermal resistance, measured in Celsius degrees per watt.
[tex]\Delta T[/tex] - Temperature gradient, measured in Celsius degress.
First, the equivalent thermal resistance needs to be determined after considering the characteristics described below:
1) B and C are configurated in parallel and in series with A and D. (Section II)
2) A and D are configurated in series. (Sections I and III)
Section II
[tex]\frac{1}{R_{II}} = \frac{1}{R_{B}} + \frac{1}{R_{C}}[/tex]
[tex]\frac{1}{R_{II}} = \frac{R_{B}+R_{C}}{R_{B}\cdot R_{C}}[/tex]
[tex]R_{II} = \frac{R_{B}\cdot R_{C}}{R_{B}+R_{C}}[/tex]
Section I
[tex]R_{I} = R_{A}[/tex]
Section III
[tex]R_{III} = R_{D}[/tex]
The equivalent thermal resistance is:
[tex]R_{T} = R_{I} + R_{II}+R_{III}[/tex]
The thermal of each component is modelled by this:
[tex]R = \frac{L}{k\cdot A}[/tex]
Where:
[tex]L[/tex] - Thickness of the brick, measured in meters.
[tex]A[/tex] - Cross-section area, measured in square meters.
[tex]k[/tex] - Thermal conductivity, measured in watts per meter-Celsius degree.
If [tex]L_{A} = 0.03\,m[/tex], [tex]L_{B} = 0.08\,m[/tex], [tex]L_{C} = 0.08\,m[/tex], [tex]L_{D} = 0.05\,m[/tex], [tex]A_{A} = 0.01\,m^{2}[/tex], [tex]A_{B} = 3\times 10^{-3}\,m^{2}[/tex], [tex]A_{C} = 7\times 10^{-3}\,m^{2}[/tex], [tex]A_{D} = 0.01\,m^{2}[/tex], [tex]k_{A} = 150\,\frac{W}{m\cdot ^{\circ}C}[/tex], [tex]k_{B} = 25\,\frac{W}{m\cdot ^{\circ}C}[/tex], [tex]k_{C} = 60\,\frac{W}{m\cdot ^{\circ}C}[/tex] and [tex]k_{D} = 60\,\frac{W}{m\cdot ^{\circ}C}[/tex], then:
[tex]R_{A} = \frac{0.03\,m}{\left(150\,\frac{W}{m\cdot ^{\circ}C} \right)\cdot (0.01\,m^{2})}[/tex]
[tex]R_{A} = \frac{1}{50}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{B} = \frac{0.08\,m}{\left(25\,\frac{W}{m\cdot ^{\circ}C} \right)\cdot (3\times 10^{-3}\,m^{2})}[/tex]
[tex]R_{B} = \frac{16}{15}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{C} = \frac{0.08\,m}{\left(60\,\frac{W}{m\cdot ^{\circ}C} \right)\cdot (7\times 10^{-3}\,m^{2})}[/tex]
[tex]R_{C} = \frac{4}{21}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{D} = \frac{0.05\,m}{\left(60\,\frac{W}{m\cdot ^{\circ}C} \right)\cdot (0.01\,m^{2})}[/tex]
[tex]R_{D} = \frac{1}{12}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{I} = \frac{1}{50} \,\frac{^{\circ}C}{W}[/tex]
[tex]R_{III} = \frac{1}{12}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{II} = \frac{\left(\frac{16}{15}\,\frac{^{\circ}C}{W} \right)\cdot \left(\frac{4}{21}\,\frac{^{\circ}C}{W}\right)}{\frac{16}{15}\,\frac{^{\circ}C}{W} + \frac{4}{21}\,\frac{^{\circ}C}{W}}[/tex]
[tex]R_{II} = \frac{16}{99}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{T} = \frac{1}{50}\,\frac{^{\circ}C}{W} + \frac{16}{99}\,\frac{^{\circ}C}{W} + \frac{1}{12}\,\frac{^{\circ}C}{W}[/tex]
[tex]R_{T} = \frac{2623}{9900}\,\frac{^{\circ}C}{W}[/tex]
Now, if [tex]\Delta T = 400\,^{\circ}C - 60\,^{\circ}C = 340\,^{\circ}C[/tex] and [tex]R_{T} = \frac{2623}{9900}\,\frac{^{\circ}C}{W}[/tex], the heat flow is:
[tex]\dot Q = \frac{340\,^{\circ}C}{\frac{2623}{9900}\,\frac{^{\circ}C}{W} }[/tex]
[tex]\dot Q = 1283.263\,W[/tex]
The heat flow from the composite wall is 1283.263 watts.
Commutation is the process of converting the ac voltages and currents in the rotor of a dc machine to dc voltages and currents at its terminals. True False
Answer:
false
Explanation:
the changing of a prisoner sentence or another penalty to another less severe
A four-cylinder, four-stroke internal combustion engine operates at 2800 RPM. The processes within each cylinder are modeled as an air-standard Otto cycle with a pressure of 14.7 lbf/in. 2 , a temperature of 80 8 F, and a volume of 0.0196 ft 3 at the beginning of compression. The compression ratio is 10, and maximum pressure in the cycle is 1080 lbf/in.Write possible Assumptions no less than three assumptionsDetermine, using a cold air-standard analysis with k 5 1.4, the power developed by the engine, in horsepower, and the mean effective pressure, in lbf/in.
Answer:
1) 287760.4 Hp
2) 18410899.5 kPa
Explanation:
The parameters given are;
p₁ = 14.7 lbf/in² = 101325.9 Pa
v₁ = 0.0196 ft³ = 0.00055501 m³
T₁ = 80°F = 299.8167 K
k = 1.4
Assumptions;
1) Air standard conditions are appropriate
2) There are negligible potential and kinetic energy changes
3) The air behaves as an ideal gas and has constant specific heat capacities of temperature and pressure
1) Process 1 to 2
Isentropic compression
T₂/T₁ = (v₁/v₂)^(1.4 - 1) = 10^0.4
p₂/p₁ = (v₁/v₂)^(1.4)
p₂ = p₁×10^0.4 = 101325.9*10^0.4 = 254519.153 Pa
T₂ = 299.8167*10^0.4 = 753.106 K
p₃ = 1080 lbf/in² = 7,446,338 Pa
Stage 2 to 3 is a constant volume process
p₃/T₃ = p₂/T₂
7,446,338/T₃ = 254519.153/753.106
T₃ = 7,446,338/(254519.153/753.106) = 22033.24 K
T₃/T₄ = (v₁/v₂)^(1.4 - 1) = 10^0.4
T₄ = 22033.24/(10^0.4) = 8771.59 K
The heat supplied, Q₁ = cv(T₃ - T₂) = 0.718*(22033.24 -753.106) = 15279.14 kJ
The heat rejected = cv(T₄ - T₁) = 0.718*(8771.59 - 299.8167) = 6082.73 kJ
W(net) = The heat supplied - The heat rejected = (15279.14 - 6082.73) = 9196.41 kJ
The power = W(net) × RPM/2*1/60 = 9196.41 * 2800/2*1/60 = 214582.9 kW
The power by the engine = 214582.9 kW = 287760.4 Hp
2) The mean effective pressure, MEP = W(net)/(v₁ - v₂)
v₁ = 0.00055501 m³
v₁/v₂ = 10
v₂ = v₁/10 = 0.00055501/10 = 0.000055501
MEP = 9196.41/(0.00055501 - 0.000055501) = 18410899.5 kPa
2. An aluminum (E = 70 GPa) tube of length 8-m is used as a simply supported column carrying a 1.2 kN axial load. If the outer diameter of the tube is 50 mm, compute the inner diameter that would provide a safety factor of 2 on buckling.
Answer:
1211 N.
Explanation:
Okay, we are given the following data or parameters or information in the question above;
=> "aluminum (E = 70 GPa) tube of length 8-m.
=> "The aluminum is used as a simply supported column carrying a 1.2 kN axial load"
The axial load to provide a factor of safety of 2 against buckling =[ (22/7)^2 × 224348 × 1000 × 70] ÷ (8 × 1000)^2 × 2.
The axial load to provide a factor of safety of 2 against buckling = 1211 N.
An AX ceramic compound has the rock salt crystal structure. If the radii of the A and X ions are 0.137 and 0.241 nm, respectively, and the respective atomic weights are 22.7 and 91.4 g/mol, what is the density (in g/cm3) of this material?
A. 0.438g/cm3
B. 0. 571g/cm3
C. 1.75g/cm3
D. 3.50g/cm3
Answer:
c) 1.75 g/cm³
Explanation:
Given that
Radii of the A ion, r(c) = 0.137 nm
Radii of the X ion, r(a) = 0.241 nm
Atomic weight of the A ion, A(c) = 22.7 g/mol
Atomic weight of the X ion, A(a) = 91.4 g/mol
Avogadro's number, N = 6.02*10^23 per mol
Solution is attached below
A 10-m long steel linkage is to be designed so that it can transmit 2 kN of force without stretching more than 5 mm nor having a stress state greater than 200 N/mm2. If the linkage is to be constructed from solid round stock, what is the minimum required diameter?
Answer:
minimum required diameter of the steel linkage is 3.57 mm
Explanation:
original length of linkage l = 10 m
force to be transmitted f = 2 kN = 2000 N
extension e = 5 mm= 0.005 m
maximum stress σ = 200 N/mm^2 = [tex]2*10^{8} N/m^{2}[/tex]
maximum stress allowed on material σ = force/area
imputing values,
200 = 2000/area
area = 2000/([tex]2*10^{8}[/tex]) = [tex]10^{-5}[/tex] m^2
recall that area = [tex]\pi d^{2} /4[/tex]
[tex]10^{-5}[/tex] = [tex]\frac{3.142*d^{2} }{4}[/tex] = [tex]0.7855d^{2}[/tex]
[tex]d^{2} = \frac{10^{-5} }{0.7855}[/tex] = [tex]1.273*10^{-5}[/tex]
[tex]d = \sqrt{1.273*10^{-5} }[/tex] = [tex]3.57*10^{-3}[/tex] m = 3.57 mm
maximum diameter of the steel linkage d = 3.57 mm
Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are 10 MPa, 450°C, and 80 m/s, and the exit conditions are 10 kPa, 92% quality, and 50 m/s. The mass flow rate of the steam is 12 kg/s.
Determine:
(a) the change in kinetic energy
(b) the power output
(c) the turbine inlet area
Answer:
a) The change in Kinetic energy, KE = -1.95 kJ
b) Power output, W = 10221.72 kW
c) Turbine inlet area, [tex]A_1 = 0.0044 m^2[/tex]
Explanation:
a) Change in Kinetic Energy
For an adiabatic steady state flow of steam:
[tex]KE = \frac{V_2^2 - V_1^2}{2} \\[/tex].........(1)
Where Inlet velocity, V₁ = 80 m/s
Outlet velocity, V₂ = 50 m/s
Substitute these values into equation (1)
[tex]KE = \frac{50^2 - 80^2}{2} \\[/tex]
KE = -1950 m²/s²
To convert this to kJ/kg, divide by 1000
KE = -1950/1000
KE = -1.95 kJ/kg
b) The power output, w
The equation below is used to represent a steady state flow.
[tex]q - w = h_2 - h_1 + KE + g(z_2 - z_1)[/tex]
For an adiabatic process, the rate of heat transfer, q = 0
z₂ = z₁
The equation thus reduces to :
w = h₁ - h₂ - KE...........(2)
Where Power output, [tex]W = \dot{m}w[/tex]..........(3)
Mass flow rate, [tex]\dot{m} = 12 kg/s[/tex]
To get the specific enthalpy at the inlet, h₁
At P₁ = 10 MPa, T₁ = 450°C,
h₁ = 3242.4 kJ/kg,
Specific volume, v₁ = 0.029782 m³/kg
At P₂ = 10 kPa, [tex]h_f = 191.81 kJ/kg, h_{fg} = 2392.1 kJ/kg[/tex], x₂ = 0.92
specific enthalpy at the outlet, h₂ = [tex]h_1 + x_2 h_{fg}[/tex]
h₂ = 3242.4 + 0.92(2392.1)
h₂ = 2392.54 kJ/kg
Substitute these values into equation (2)
w = 3242.4 - 2392.54 - (-1.95)
w = 851.81 kJ/kg
To get the power output, put the value of w into equation (3)
W = 12 * 851.81
W = 10221.72 kW
c) The turbine inlet area
[tex]A_1V_1 = \dot{m}v_1\\\\A_1 * 80 = 12 * 0.029782\\\\80A_1 = 0.357\\\\A_1 = 0.357/80\\\\A_1 = 0.0044 m^2[/tex]
An example of a transient analysis involving the 1st law of thermodynamics and conservation of mass is the filling of a compressed air tank. Assume that an air tank is being filled using a compressor to a pressure of 5 atm, and that it is being fed with air at a temperature of 25°C and 1 atm pressure. The compression process is adiabatic. Will the temperature of the air in the tank when it is done being filled i.e. once the pressure in the tank reaches 5 atm), be greater than, equal to, or less that the temperature of the 25°C air feeding the compressor?
A. Greater than 25°C
B. Unable to determine
C. Same as 25°C
D. Less than 25°C
Answer:
The temperature will be greater than 25°C
Explanation:
In an adiabatic process, heat is not transferred to or from the boundary of the system. The gain or loss of internal heat energy is solely from the work done on the system, or work done by the system. The work done on the system by the environment adds heat to the system, and work done by the system on its environment takes away heat from the system.
mathematically
Change in the internal energy of a system ΔU = ΔQ + ΔW
in an adiabatic process, ΔQ = 0
therefore
ΔU = ΔW
where ΔQ is the change in heat into the system
ΔW is the work done by or done on the system
when work is done on the system, it is conventionally negative, and vice versa.
also W = pΔv
where p is the pressure, and
Δv = change in volume of the system.
In this case, work is done on the gas by compressing it from an initial volume to the new volume of the cylinder. The result is that the temperature of the gas will rise above the initial temperature of 25°C
For this given problem, if the yield strength is now 45 ksi, using Distortion Energy Theory the material will _______ and using the Maximum Shear Stress Theory the material will __________
a. fail / not fail
b. fail /fail
c. not fail/fail
d. not fail/not fail
Answer:
Option A - fail/ not fail
Explanation:
For this given problem, if the yield strength is now 45 ksi, using Distortion Energy Theory the material will _fail______ and using the Maximum Shear Stress Theory the material will ___not fail_______
help mhee why are you u an enigner
Answer:
help me why are you an enginer
Explanation:
because lives
Engineers Sophia and Giles are modifying a process to make concentrated apple cider starting from a slurry - a slurry is a mixture of solids in a liquid that can normally be pumped. A slurry made with apples having a mass fraction of 0.422 and the balance water is fed to a juicer at a rate of 27.3 kg/min. Seventy percent of the apples entering the juicer leave as part of the solid waste stream (containing apples and water). The primary product from the juicer is cider (32.9 wt% apples and 67.1 wt% water). The cider is sent to an evaporator where concentrate - apple concentration increases to 49.1 wt% - is produced along with a stream of pure water that is recycled. The pure water stream leaving the evaporator is mixed with fresh water entering the process. The combined water stream mixes with pristine apples entering the process to create the slurry. Determine the following three unknowns:
1. Mass fraction of apple in the solid waste
2. Total flow rate of the concentrate (kg/min)
3. Flow rate of pure water entering the overall system (kg/min)
Answer:
1) Mass fraction of apple in the solid waste = 0.644
2) Total flow rate of the concentrate = 12.89 kg/min
3) Flow rate of pure water entering the overall system = 9.434 kg/min
Explanation:
Mass fraction of the slurry = 0.422
Rate at which the balance water is fed to a juicer, m = 27.3 kg/min
Stream fed to juice contains (0.422 * 27.3) = 11.5206 kg/min apple
Stream fed to juice contains (27.3 - 11.5206) = 15.7794 kg/min water
70% of the apples entering the juicer leave as part of the solid waste stream
Amount of Apples leaving the stream as part of the solid waste stream,
W = 0.7 * 11.5206
W = 8.06442 kg/min
Overall balance on juicer: m = p + W
p = m - W
p = 27.3 - 8.06442
p = 19.236 kg/min
p stream contains 32.9 wt% apples and 67.1 wt% water
1) Mass fraction of apple in the solid waste:
Let x = Mass fraction of apple in the solid waste
Apple in m stream = Apple in p stream + Apple in W stream
11.5206 = (0.329 * 19.236) + (x * 8.06442)
11.5206 = 6.33 + 8.06442x
8.06442x = 11.5206 - 6.33
x = 0.644
2) Total flow rate of the concentrate (kg/min)
Cider sent to evaporator where concentrate increases from 32.9 wt% to 49.1 wt%
Solid balance; 0.329 p = 0.491 c
0.329 * 19.236 = 0.491 c
c = 12.89 kg/min
Total flow rate of the concentrate = 12.89 kg/min
3 Flow rate of pure water entering the overall system (kg/min)
Overall balance for evaporator: p = v + c
Where P is the pure water from evaporator
v = p - c
v = 19.236 - 12.89
v = 6.346 kg/min
Rate of Water entering into the juicer = (1 - 0.422) *27.3 = 15.78 kg/min
Pure water from evaporator, v = 6.346 kg/min
Flow rate of pure water entering the overall system = 15.78 - 6.346
Flow rate of pure water entering the overall system = 9.434 kg/min
An inverted tee lintel is made of two 8" x 1/2" steel plates. Calculate the maximum bending stress in tension and compression when the lintel carries a total uniformly distributed load of 10000 lb on a simple span of 6 ft. Also, calculate the average shear stress at the neutral axis and the average shear stresses at the web and the flange
Answer:
hello your question lacks some information attached is the complete question
A) (i)maximum bending stress in tension = 0.287 * 10^6 Ib-in
(ii) maximum bending stress in compression = 0.7413*10^6 Ib-in
B) (i) The average shear stress at the neutral axis = 0.7904 *10 ^5 psi
(ii) Average shear stress at the web = 18.289 * 10^5 psi
(iii) Average shear stress at the Flange = 1.143 *10^5 psi
Explanation:
First we calculate the centroid of the section,then we calculate the moment of inertia and maximum moment of the beam( find attached the calculation)
A) Calculate the maximum bending stress in tension and compression
lintel load = 10000 Ib
simple span = 6 ft
( (moment of inertia*Y)/ I ) = MAXIMUM BENDING STRESS
I = 53.54
i) The maximum bending stress (fb) in tension=
= [tex]\frac{M_{mm}Y }{I}[/tex] = [tex]\frac{6.48 * 10^6 * 2.375}{53.54}[/tex] = 0.287 * 10^6 Ib-in
ii) The maximum bending stress (fb) in compression
= [tex]\frac{M_{mm}Y }{I}[/tex] = [tex]\frac{6.48 *10^6*(8.5-2.375)}{53.54}[/tex] = 0.7413*10^6 Ib-in
B) calculate the average shear stress at the neutral axis and the average shear stresses at the web and the flange
i) The average shear stress at the neutral axis
V = [tex]\frac{wL}{2}[/tex] = [tex]\frac{1000*6*12}{2}[/tex] = 3.6*10^5 Ib
Ay = 8 * 0.5 * (2.375 - 0.5 ) + 0.5 * (2.375 - [tex]\frac{0.5}{2}[/tex] ) * [tex]\frac{(2.375 - (\frac{0.5}{2} ))}{2}[/tex]
= 5.878 in^3
t = VQ / Ib = ( 3.6*10^5 * 5.878 ) / (53.54 8 0.5) = 0.7904 *10 ^5 psi
ii) Average shear stress at the web ( value gotten from the shear stress at the flange )
t = 1.143 * 10^5 * (8 / 0.5 ) psi
= 18.289 * 10^5 psi
iii) Average shear stress at the Flange
t = VQ / Ib = [tex]\frac{3.6*10^5 * 8*0.5*(2.375*(0.5/2))}{53.54 *0.5}[/tex]
= 1.143 *10^5
In the design of a median of a major right of way where the designer wants to use low irrigation system of landscaping would be a positive design parameter. True or False
Answer:
True
Explanation:
Design parameter define design, cost, benefits and risk associated with the design. Low irrigation system is one in which water flows from low pressure in the lines. This type of system is suitable for slow water irrigation system and plants which are near to the water system. Using positive design parameter designer may wish to design low irrigation system of landscaping.
Identify the correct statements in the context of friction factors of laminar and turbulent flows
a) In turbulent flow, the tubes with rough surfaces have much higher friction factors than the tubes with smooth surfaces
b) In turbulent flow, the tubes with rough surfaces have much lower friction factors than the tubes with smooth surfaces.
c) In laminar flow, the friction factor is dependent on the surface roughness
d) In laminar flow, the friction factor is independent of the surface roughness.
Answer:
a) In turbulent flow, the tubes with rough surfaces have much higher friction factors than the tubes with smooth surfaces.
Explanation:
Turbulent flow is a type of fluid flow in which fluid will undergo irregular fluctuations. The tubes with rough surfaces have higher friction factors than the tubes with smooth surfaces. In laminar flow the effect of effect of surface roughness is negligible on friction factors.