Answer:
The units on the rate of heat transfer are Joule/second, also known as a Watt.
Explanation:
Heat flow is calculated using the rock thermal conductivity multiplied by the temperature gradient. The standard units are mW/m2 = milli Watts per meter squared. Thus, think of a flat plane 1 meter by 1 meter and how much energy is transferred through that plane is the amount of heat flow.
hope it helps .
stay safe healthy and happy..The rate of heat transfer is measured in Joules per second, also known as Watts.
What is heat transfer?Heat transfer is a thermal engineering discipline that deals with the generation, use, conversion, and exchange of thermal energy between physical systems.
Heat transfer mechanisms include thermal conduction, thermal convection, thermal radiation, and energy transfer via phase changes.
The rate of heat transfer through a unit thickness of material per unit area per unit temperature difference is defined as thermal conductivity. Thermal conductivity varies with temperature and is measured experimentally.
Heat is typically transferred in a combination of these three types and occurs at random. Heat transfer rate is measured in Joules per second, also known as Watts.
Thus, Joules per second or watts is the unit of rate of heat transfer.
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How do Machine Learning and Artificial Intelligence (AI) technologies help businesses use their enterprise data effectively?
Answer:
Explanation:
Application of artificial intelligence in business
You can use AI technologies to:
Improve customer services - eg use virtual assistant programs to provide real-time support to users (for example, with billing and other tasks).
Automate workloads - eg collect and analyse data from smart sensors, or use machine learning (ML) algorithms to categorise work, automatically route service requests, etc.
Optimise logistics - eg use AI-powered image recognition tools to monitor and optimise your infrastructure, plan transport routes, etc.
Increase manufacturing output and efficiency - eg automate production line by integrating industrial robots into your workflow and teaching them to perform labour-intensive or mundane tasks.
Prevent outages - eg use anomaly detection techniques to identify patterns that are likely to disrupt your business, such as an IT outage. Specific AI software may also help you to detect and deter security intrusions.
Predict performance - eg use AI applications to determine when you might reach performance goals, such as response time to help desk calls.
Predict behaviour - eg use ML algorithms to analyse patterns of online behaviour to, for example, serve tailored product offers, detect credit card fraud or target appropriate adverts.
Manage and analyse your data - eg AI can help you interpret and mine your data more efficiently than ever before and provide meaningful insight into your assets, your brand, staff or customers.
Improve your marketing and advertising - for example, effectively track user behaviour and automate many routine marketing tasks.
Machine learning is an Artificial intelligence-powered system that is based on a similar concept and able to learn from the intelligence provided by humans.
The AI systems are used to perform complex tasks in a way that is similar to humans but with precision. The AI-enabled machinery learning can boost sales and enhance the marketing campaign of any business or organization. It can develop a faster road map.Learn more about Machine Learning and Artificial Intelligence (AI) technologies.
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Case Study # 1: Cadbury Crisis Management (Worm Controversy)
In India chocolate consumption was very low in the early 90’s but as the decade advanced the consumption drastically increased. The late 90’s witnessed a good chocolate market condition. The chocolate market in India is dominated by two multinational companies – Cadbury and Nestle. The national companies – Amul and Campco are other candidates in this race. Cadbury holds more than 70% of the total share of the market. Nestle has emerged by holding almost 20% of the total share. Apart from chocolate segment, there is also a big confectionery segment which is flooded by companies like Parry’s, Ravalgaon, Candico and Nutrine. All these are leading national players. The multinational companies like the Cadbury, Nestle and Perfetti are the new entrants in the sugar confectionery market. (Management paradise) There are several others which have a minor share in these two segments. According to statistics, the chocolate consumption in India is extremely low. If per capita consumption is considered, it comes to only 160gms in the urban areas. This amount is very low compared to the developed countries where the per capita consumption is more than 8-10kg. Observing this fact it would not be appropriate to consider the rural areas of India as it will be extremely low. This low consumption is owing to the notion behind consuming chocolates. Indians eat chocolates as indulgence and not as snack food. The major target population is the children. India has witnessed a slow growth rate of about 10% pa from the 70’s to the 80’s. But as the century advanced the market stagnated. This was the time when Cadbury launched its product- Dairy Milk as an anytime product rather than an occasional luxury. All the advertisements of Dairy Milk paid a full attention to adults and not children. And this proved to be the major breakthrough for Cadbury as it tried to break the conventional ideas of the Indians about chocolate.
The Worm Controversy
On October 2003, just a month before Diwali, the Food and Drug Administration Commissioner received complaints about infestation in two bars of Cadbury Dairy Milk, Cadbury India’s flagship brand with over 70% market share. He ordered an enquiry and went directly to the media with a statement. Over the following 3-week period, resultant adverse media coverage touched close to 1000 clips in print and 120 on TV news channels. In India, where Cadbury is synonymous with chocolate, the company’s reputation and credibility was under intense scrutiny. Sales volumes came down drastically in the first 10 weeks, which was the festival season; retailer stocking and display dropped, employee morale – especially that of the sales team – was shaken.
The challenge was to restore confidence in the key stakeholders (consumers, trade and employees, particularly the sales team) and build back credibility for the corporate brand through the same channels (the media) that had questioned it. In defense, Cadbury issued a statement that the infestation was not possible at the manufacturing stage and poor storage at the retailers was the most likely cause of the reported case of worms. But the FDA didn’t buy that. FDA commissioner, Uttam Khobragade told CNBC-TV18, “It was presumed that worms got into it at the storage level, but then what about the packing – packaging was not proper or airtight, either ways it’s a manufacturing defect with unhygienic conditions or improper packaging.” That was followed by allegations and counter-allegations between Cadbury and FDA. The heat of negative publicity melted Cadbury’s sales by 30 per cent, at a time when it sees a festive spike of 15 per cent. For the first time, Cadbury’s advertising went off air for a month and a half after Diwali, following the controversy. Consumers seemed to ignore their chocolate cravings.
Question:
1. How will the Cadbury can restore the confidence of the consumer?
Make an elaborate plan on how you are going to do it. Use the Decision-making Process. a) Diagnose problem
b) Analyze environment
c) Articulate problem or opportunity d) Develop viable alternatives
e) Evaluate alternatives f) Make a choice
g) Implement decision
h) Evaluate and adapt decision results
dentify the recommended practices when putting a tip on a micropipette. Select one or more: Gently push the micropipette into the tip and tap lightly to load the tip. Hold the micropipette at a 45 degree angle to the tip rack. Use the tip size designed for the micropipette size in use. Remove the tip from the rack and place it on micropipette by hand.
Answer:
Gently push the micropipette into the tip box and tag tightly to load the tip.
Explanation:
The recommended practice when putting a tip on a micropipette is ; Gently push the micropipette into the tip box and tag tightly to load the tip.
Given that it is not advisable to remove tip from rack so as not to contaminate it, if we want to put a tip on a micropipette we should gently push the micropipette into the tip box.
Which of the following are major components of a Class II BSC: A. Cabinet blower switch B. Foot support C. Drain spillage trough (catch basin) D. Rear grille E. Temperature control
Answer:
Cabinet blower switch ( A )
Explanation:
A major component of a class II BSC ( Biological safety cabinet ) is Cabinet blower switch because the Cabinet blower is an integral part of a class II BSC hence the switch is also a major component.
Class II BSC provides protection for the user, environment and sample to be manipulated in the laboratory ( mostly ; Pharmaceutical laboratories, Microbiology laboratories )
The term variation describes the degree to which an object or idea differs from others of the same type or from a standard.
a. True
b. False
Discuss typical advantages and disadvantages of an irrigation system?
how are hybrid and gasoline cars alike
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how do you know when an equation is (In)
The National Weather Service has issued an alert for a severe storm that will bring 100 mm of rainfall in one hour. A farmer in the area is trying to decide whether to sand bag the creek that drains the 40 acres of row crops. The soil for the drainage area is a sandy clay loam and has a porosity of 0.398, effective porosity of 0.330, suction pressure of 52.3 cm, a hydraulic conductivity of 0.25 cm/hr and an effective saturation of 90%. Assuming that ponding occurs instantaneously, estimate the total depth of direct runoff in mm from the event using the Green-Ampt infiltration model.
a. 80
b. 89
c. 76
d. 72
If the same type of thermoplastic polymer is being tensile tested and the strain rate is increased, it will: g
Answer:
It would break I think need to try it out
Explanation:
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:
Given that the section modulus of the wide flange beam is 200 in^3 the lightest beam possible that can satisfy the section modulus must have a section modulus ≥ 200 in^3. also the value of the section modulus must be approximately closest to 200in^3
From wide flange Beam table ( showing the section modulus )
The beam that can satisfy the condition is W18 × 106 because its section modulus ( s ) = 204 in^3
1. Using the formula above, complete this task.
Concrete is currently sold in increments of 12 yd'. Concrete current cost is $45 per V2 yd. How much would it cost a Shameka's Construction Company to cement a pad size 18ft x 20 ft. floor, 4 inches thick?
Answer:
gfbhjdskmlgtg
Explanation:
grtwhjyeywhtagsfdd
What happens to resistance in the strain gauge and voltage drop from a connected Wheatstone bridge if you were to pull the strain gauge along the long axis
Answer:
Resistance and voltage drop will still continue to rise, although at a slower pace than on the desired axis.
Explanation:
Pulling the strain gauge in the long axis causes the wires to elongate/thin, the effect of this is that it will lead to an increase in resistance and voltage drop (V = I*R).
As a result of the resultant effect, resistance and voltage drop will still continue to rise, although at a slower pace than on the desired axis, such as the long axis.
A frost free, 17 cu. ft. refrigerator-freezer uses energy at a rate of 500. watts when you hear the compressor running. If the fridge runs for 200. hours per month, how many kilowatt-hours of energy does the refrigerator use each month
Answer:
100 kWh
Explanation:
Since the freezer has a rating of 500 watts and runs for 200 hours in a month, the energy consumption can be gotten by getting the product of the rating of the freezer in kilowatts and the amount of time the fridge is on per month.
The rating of the freezer = 500 watts = 0.5 kW, time = 200 h
Energy consumption = rating * time = 0.5 kW * 200 h
Energy consumption = 100 kWh
Therefore the refrigerator uses 100 kWh per month
what happen to the clutch system when you step-on and releasing the clutch pedal?
Answer:
Step On: Your foot forces the clutch pedal down and then causes it to take up the slack. This, in turn, causes the clutch friction disk to slip, creating heat and ultimately wearing your clutch out.
Step Off: When the clutch pedal is released, the springs of the pressure plate push the slave cylinder's pushrod back, which forces the hydraulic fluid back into the master cylinder.
6.D1 A large tower is to be supported by a series of steel wires. It is estimated that the load on each wire will be 13,300 N (3000 lbf). Determine the minimum required wire diameter assuming a factor of safety of 2 and a yield strength of 860 MPa (125,000 psi).
Answer:
6.33 mm
Explanation:
Stress is an internally resistive force produced by the molecules of the object to resist the deformation when an amount of load acts on the object. The SI unit of stress is measured in Pascal.
Given that force (F) = 13300 N, factor of safety (λ) = 2, yield strength (σy) = 860 MPa
The working stress [tex](\sigma_w)=\frac{\sigma_y}{\lambda}=\frac{860\ MPa}{2}=430\ MPa[/tex]
Let d be the minimum diameter, hence it is calculated using:
[tex]\sigma_w=\frac{F}{A}\\\\430 *10^6=\frac{13300}{A}\\\\A=30.93*10^{-6}\ m^2\\\\A=area=\frac{\pi d^2}{4} \\\\30.93*10^{-6}\ m^2=\frac{\pi d^2}{4} \\\\d=\sqrt{\frac{4*30.93*10^{-6}}{\pi } } \\\\d=0.0063\ m=6.3\ mm[/tex]
QUESTION 1
Outcome: Direct Current Motors.
1.1 Identify the parts of the direct current motor below.
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4 An approach to a pretimed signal has 30 seconds of effective red, and D/D/1 queuing holds. The total delay at the approach is 83.33 veh-s/cycle and the saturation flow rate is 1000 veh/h. If the capacity of the approach equals the number of arrivals per cycle, determine the approach flow rate and cycle length.
Answer:
Following are the responses to the given question:
Explanation:
Effective red duration is applied each cycle r=30 second D/D/1 queuing
In total, its approach delay is 83.33 sec vehicle per cycle
Flow rate(s) of saturated = 1,000 vehicles each hour
Total vehicle delay per cycle[tex]= \frac{v \times 30^2}{2(1-\frac{v}{0.2778})}[/tex]
[tex]\to \frac{v\times 30^2}{2(1-\frac{v}{0.2778})}= 83.33\\\\\to 900v=166.66-599.928v\\\\\to v=0.111 \frac{veh}{sec}\\\\[/tex]
The flow rate for such total approach is 0.111 per second.
The overall flow velocity of the approach is 400 cars per hour
The approach capacity refers to the number of arrivals per cycle.
Environmentally friendly time ratio to cycle length:
[tex],\frac{g}{C} \ is = \frac{400}{1000}=0.4\\\\r= c-g\\\\30\ sec =C - 0.4 C\\\\C=50 \ sec[/tex]
what is Geography? pliz help
Answer:
hope it's helpful please like and Follow me
Answer:
Geography is the science that studies and describes the surface of the Earth in its physical, current and natural aspect, or as a place inhabited by humanity.
1. A hydro facility operates with an elevation difference of 50 m and a flow rate of 500 m3/s. If the rotational speed is 90 RPM, find the most suitable type of turbine and estimate the power output of the arrangement
Answer:
a) Pelton Turbine
b) [tex]P=2.42*10^{5}KW[/tex]
Explanation:
From the question we are told that:
Height [tex]h=50[/tex]
Flow Rate [tex]R= 500 m^3/s[/tex]
Rotational speed [tex]\omega=\90 RPM[/tex]
Let
Density of water
[tex]\rho=1000[/tex]
Generally the equation for momentum is mathematically given by
[tex]P=\rho gRh[/tex]
[tex]P=1000*9.81*500*50[/tex]
[tex]P=2.42*10^{5}KW[/tex]
An air-standard Diesel cycle engine operates as follows: The temperatures at the beginning and end of the compression stroke are 30 °C and 700 °C, respectively. The net work per cycle is 590.1 kJ/kg, and the heat transfer input per cycle is 925 kJ/kg. Determine the a) compression ratio, b) maximum temperature of the cycle, and c) the cutoff ratio, v3/v2.
This question is incomplete, the complete question is;
An air-standard Diesel cycle engine operates as follows: The temperatures at the beginning and end of the compression stroke are 30 °C and 700 °C, respectively. The net work per cycle is 590.1 kJ/kg, and the heat transfer input per cycle is 925 kJ/kg. Determine the a) compression ratio, b) maximum temperature of the cycle, and c) the cutoff ratio, v3/v2.
Use the cold air standard assumptions.
Answer:
a) The compression ratio is 18.48
b) The maximum temperature of the cycle is 1893.4 K
c) The cutoff ratio, v₃/v₂ is 1.946
Explanation:
Given the data in the question;
Temperature at the start of a compression T₁ = 30°C = (30 + 273) = 303 K
Temperature at the end of a compression T₂ = 700°C = (700 + 273) = 973 K
Net work per cycle [tex]W_{net[/tex] = 590.1 kJ/kg
Heat transfer input per cycle Qs = 925 kJ/kg
a) compression ratio;
As illustrated in the diagram below, 1 - 2 is adiabatic compression;
so,
Tγ[tex]^{Y-1[/tex] = constant { For Air, γ = 1.4 }
hence;
⇒ V₁ / V₂ = [tex]([/tex] T₂ / T₁ [tex])^{\frac{1}{Y-1}[/tex]
so we substitute
⇒ V₁ / V₂ = [tex]([/tex] 973 K / 303 K [tex])^{\frac{1}{1.4-1}[/tex]
= [tex]([/tex] 3.21122 [tex])^{\frac{1}{0.4}[/tex]
= 18.4788 ≈ 18.48
Therefore, The compression ratio is 18.48
b) maximum temperature of the cycle
We know that for Air, Cp = 1.005 kJ/kgK
Now,
Heat transfer input per cycle Qs = Cp( T₃ - T₂ )
we substitute
925 = 1.005( T₃ - 700 )
( T₃ - 700 ) = 925 / 1.005
( T₃ - 700 ) = 920.398
T₃ = 920.398 + 700
T₃ = 1620.398 °C
T₃ = ( 1620.398 + 273 ) K
T₃ = 1893.396 K ≈ 1893.4 K
Therefore, The maximum temperature of the cycle is 1893.4 K
c) the cutoff ratio, v₃/v₂;
Since pressure is constant, V ∝ T
So,
cutoff ratio S = v₃ / v₂ = T₃ / T₂
we substitute
cutoff ratio S = 1893.396 K / 973 K
cutoff ratio S = 1.9459 ≈ 1.946
Therefore, the cutoff ratio, v₃/v₂ is 1.946
Please send the solution quickly
Answer:
answer 2
Explanation:
A step-up transformer has 20 primary turns and 400 secondary turns. If the primary current is 30 A, what is the secondary current
In an ideal transformer, the ratio of input voltage to output voltage is equal to the ratio of the number of turns in primary coil to number of turns in the secondary coil. Therefore, the secondary current in the given case is 1.5 A.
What is secondary current ?Secondary current refers to the electric current that flows in the secondary winding of a transformer. A transformer is a device that transfers electrical energy from one circuit to another by means of electromagnetic induction.
It consists of two or more coils of insulated wire, called windings, that are wound around a common magnetic core. In a transformer, an alternating current (AC) flows through the primary winding, which produces a magnetic field that induces a voltage in the secondary winding.
The secondary current in the above given case is 1.5 A.
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I ran across this symbol in some Electrical wiring documents and I am unaware of what this means. Any help?
Answer:
Opened Push-button Switch (i.e. a PTM Switch)
Explanation:
Tha's just another symbol for a switch, but this one specifies that the switch is a push-button type of switch.
Since it's not touching and completing the line, the state of the switch is initially open.
The output side of an ideal transformer has 35 turns, and supplies 2.0 A to a 24-W device. Ifthe input is a standard wall outlet, calculate the number of turns on the input side, and the currentdrawn from the outlet.
Answer:
The current drawn from the outlet is 0.2 A
The number of turns on the input side is 350 turns
Explanation:
Given;
number of turns of the secondary coil, Ns = 35 turns
the output current, [tex]I_s[/tex] = 2 A
power supplied, [tex]P_s[/tex] = 24 W
the standard wall outlet in most homes = 120 V = input voltage
For an ideal transformer; output power = input power
the current drawn from the outlet is calculated;
[tex]I_pV_p = P_s\\\\I_p = \frac{P_s}{V_p} = \frac{24}{120} = 0.2 \ A[/tex]
The number of turns on the input side is calculated as;
[tex]\frac{N_p}{N_s} = \frac{I_s}{I_p} \\\\N_p = \frac{N_sI_s}{I_p} \\\\N_p = \frac{35 \times 2}{0.2} \\\\N_p = 350 \ turns[/tex]
1.8 A water flow of 4.5 slug/s at 60 F enters the condenser of steam turbine and leaves at 140 F. Determine the heat transfer rate (Btu/hr)
Answer:
[tex]Hr=4.2*10^7\ btu/hr[/tex]
Explanation:
From the question we are told that:
Water flow Rate [tex]R=4.5slug/s=144.78ib/sec[/tex]
Initial Temperature [tex]T_1=60 \textdegree F[/tex]
Final Temperature [tex]T_2=140 \textdegree F[/tex]
Let
Specific heat of water [tex]\gamma= 1[/tex]
And
[tex]\triangle T= 140-60[/tex]
[tex]\triangle T= 80\ Deg.F[/tex]
Generally the equation for Heat transfer rate of water [tex]H_r[/tex] is mathematically given by
Heat transfer rate to water= mass flow rate* specific heat* change in temperature
[tex]H_r=R* \gamma*\triangle T[/tex]
[tex]H_r=144.78*80*1[/tex]
[tex]H_r=11582.4\ btu/sec[/tex]
Therefore
[tex]H_r=11582.4\ btu/sec*3600[/tex]
[tex]Hr=4.2*10^7\ btu/hr[/tex]
Analyze the boundary work done during the process having a rigid tank contains air at 500 kPa and 150°C. As a result of heat transfer to the surroundings, the temperature and pressure inside the tank drop to 65°C and 400 kPa, respectively.
Complete Question
Analyze the boundary work done during the process having a rigid tank contains air at 500 kPa and 150°C. As a result of heat transfer to the surroundings, the temperature and pressure inside the tank drop to 65°C and 400 kPa, respectively.
Determine the boundary work done during this process and heat Lose
Answer:
a) [tex]W=0[/tex]
b) [tex]dQ=-61.03KJ/kg[/tex]
Explanation:
From the question we are told that:
Pressure of air [tex]P_1=500kpa[/tex]
Temperature of Air [tex]T_2=150°C[/tex]
Pressure drop [tex]P_2=400kpa[/tex]
Temperature of drop [tex]T_2=65 \textdegree C[/tex]
Generally the Constant Volume Process is mathematically given by
[tex]V_1=V_2=V[/tex]
Therefore
a)
Generally the equation for boundary work w is mathematically given by
[tex]W=pdv[/tex]
[tex]W=P(V_2-V_1)[/tex]
[tex]W=P(V_V)[/tex]
[tex]W=0KJ[/tex]
b)
Generally the equation for Heat Change is mathematically given by
[tex]dQ=dU+dW[/tex]
[tex]dQ=dU[/tex]
[tex]dQ=C_v(T_2-T_1)[/tex]
Where
C_v=Specific Heat capacity of Air
[tex]C_v=0.718 kJ/kg K[/tex]
[tex]dQ=0.718(338-423)[/tex]
[tex]dQ=-61.03KJ/kg[/tex]
The object in ....................... shadow is not seen completely
Answer:
Dark shadow
Explanation:
Shadow is nothing but space when the light is blocked by an opaque object. It is just that part where light does not reach. When you stand in the sun, you are able to see your shadow behind you. ... This is because our body is opaque and does not allow the light to pass through it
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A 2-m-internal-diameter spherical tank made of 0.5-cm-thick stainless steel (k = 15 W/m·K) is used to store iced water at 0°C in a room at 20°C. The walls of the room are also at 20°C. The outer surface of the tank is black (emissivity ε = 1), and heat transfer between the outer surface of the tank and the surroundings is by natural convection and radiation. Assuming the entire steel tank to be at 0°C and thus the thermal resistance of the tank to be negligible, determine
(a) the rate of heat transfer to the iced water in the tank and
(b) the amount of ice at 0°C that melts during a 24-h period. The heat of fusion of water is 333.7 kJ/kg. Now, consider a 2-m internal diameter double- walled spherical tank configuration is used instead to store iced water at 0°C in a room at 20°C. Each wall is 0.5 cm thick, and the 1.5-cm-thick air space between the two walls of the tank is evacuated in order to minimize heat transfer. The surfaces surrounding the evacuated space are polished so that each surface has an emissivity of 0.15. The temperature of the outer wall of the tank is measured to be 20°C. Assuming the inner wall of the steel tank to be at 0°C, determine
(c) the rate of heat transfer to the iced water in the tank for this double-walled tank configuration and
(d) the amount of ice at 0°C that melts during a 24-h period for this double-walled tank configuration.
Answer:
a. 6.48 kW b. 1678.34 kg c. 777.92 W d. 201.42 kg
Explanation:
(a) the rate of heat transfer to the iced water in the tank
The rate of heat transfer to the outer surface of the spherical tank is P = P₁ + P₂ where P₁ = rate of heat transfer to the outer surface by radiation and P₂ = rate of heat transfer to the outer surface by convection through air
P₁ = εσAT⁴ where ε = emissivity of outer surface ε= 1, σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m-K⁴, A = area of outer surface of spherical tank = 4πR² where R = outer radius of spherical tank = inner radius + thickness = inner diameter/2 + 5 cm = 2 m/2 + 0.05 m = 1 m + 0.05 m = 1.05 m and T = temperature of surroundings = 20 °C = 273 + 20 = 293 K.
P₁ = εσAT⁴
P₁ = 1 × 5.67 × 10⁻⁸ W/m-K⁴ × 4π(1.05 m)² × (293 K)⁴
P₁ = 1 × 5.67 × 10⁻⁸ W/m-K⁴ × 4π(1.1025 m²) × 7370050801 K⁴
P₁ = 184285909263.7647π × 10⁻⁸ W
P₁ = 578951258703.16 × 10⁻⁸ W
P₁ = 5789.51 W
P₂ = hA(T - T₁) where h = coefficient of thermal convection of air = 2.5 W/m²-K, A = outer surface area of spherical tank = 4πR², T = temperature of surroundings = 20 °C = 273 + 20 = 293 K and T₁ = temperature of outer surface of spherical tank = 0 °C = 273 + 0 = 273 K.
P₂ = hA(T - T₁)
P₂ = 2.5 W/m²-K × 4π(1.05 m)² × (293 K - 273 K)
P₂ = 2.5 W/m²-K × 4π(1.1025 m²) × 20 K
P₂ = 220.5π W
P₂ = 692.72 W
So, P = P₁ + P₂ = 5789.51 W + 692.72 W = 6482.23 W
Since we are neglecting the thermal resistance of the spherical tank, the rate of heat absorption of the outer surface equals the rate of heat absorption in the inner surface. The rate of heat absorption at the inner surface equals the rate of heat transfer to the iced water.
So, rate of heat transfer to the iced water = P = 6482.23 W = 6.48223 kW 6.48 kW
(b) the amount of ice at 0°C that melts during a 24-h period. The heat of fusion of water is 333.7 kJ/kg.
Since the amount of heat, Q = Pt where P = heat transfer rate to iced water = 6482.23 W and t = time = 24 h = 24 h × 60 min/h × 60 s/min = 86400 s.
Also, Q = the latent heat required to melt the ice at 0 °C = mL where m = mass of ice melted and L = latent heat of fusion of ice = 333.7 kJ/kg
So, Pt = mL
m = Pt/L
= 6482.23 W × 86400 s/333.7 × 10³ J/kg
= 560064672/333.7 × 10³
= 1678.34 kg
(c) the rate of heat transfer to the iced water in the tank for this double-walled tank configuration
Since P is the rate of heat transfer to the outer surface, this is also the rate of heat transfer to the outer 0.5 cm thick wall = P₃ = 6482.23 W
P₃ = kA(T - T₃)/d where k = thermal conductivity of outer wall = 15 W/m²-K
A = surface area of outer wall = 4πR'² where R' = radius of outer wall = radius of inner wall + thickness of inner wall + thickness of vacuum + thickness of outer wall = 2.0 m/2 + 0.5 cm + 1.5 cm + 0.5 cm = 1 m + 2.5 cm = 1 m + 0.025 m = 1.025 m, T = temperature of surroundings = 20 °C = 273 + 20 = 293 K, T₃ = temperature of inner surface of outer wall of spherical tank and d = thickness of outer surface of tank = 0.5 cm = 0.05 m
P₃ = kA(T - T₃)/d
making T₃ subject of the formula, we have
P₃d = kA(T - T₃)
P₃d/kA = (T - T₃)
T₃ = T - P₃d/kA
substituting the values of the variables into the equation, we have
T₃ = 293 K - 6482.23 W × 0.05 m/[15 W/m-K × 4π(1.025 m)²]
T₃ = 293 K - 324.1115 Wm/[15 W/m-K × 4π(1.050625 m²)]
T₃ = 293 K - 324.1115 Wm/[63.0375π W/m-K)]
T₃ = 293 K - 324.1115 Wm/[198.0381 W/m-K)]
T₃ = 293 K - 1.64 K
T₃ = 291.36 K
Since the 1.5 cm thick air space is evacuated, all the heat gets to the inner 0.5 cm thick wall by radiation.
So P = εσAT₃⁴
P₄ = εσAT₃⁴ where ε = emissivity of outer surface ε = 0.15, σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m-K⁴, A = area of inner surface of outer wall of spherical tank = 4πR"² where R" = outer radius of inner thick wall of spherical tank = inner radius + thickness of inner wall = inner diameter/2 + 0.5 cm = 2 m/2 + 0.005 m = 1 m + 0.005 m = 1.005 m and T = temperature of outer wall = 291.36 K.
P₄ = 0.15 × 5.67 × 10⁻⁸ W/m-K⁴ × 4π(1.005 m)² × (291.36 K)⁴
P₄ = 0.15 × 5.67 × 10⁻⁸ W/m-K⁴ × 4π(1.010025 m²) × 7206422389.51 K⁴
P₄ = 24762024365.028π × 10⁻⁸ W
P₄ = 77792193833.18 × 10⁻⁸ W
P₄ = 777.92 W
Now P₄ is the heat transfer rate to the inner surface which is at temperature T₄
Since T₄ = 0 °C, P₄ is the rate of heat transfer to the iced water
So, rate of heat transfer to the iced water P₄ = 777.92 W
(d) the amount of ice at 0°C that melts during a 24-h period for this double-walled tank configuration
Since the amount of heat, Q = P₄t where P₄ = heat transfer rate to iced water = 777.92 W and t = time = 24 h = 24 h × 60 min/h × 60 s/min = 86400 s.
Also, Q = the latent heat required to melt the ice at 0 °C = mL where m = mass of ice melted and L = latent heat of fusion of ice = 333.7 kJ/kg
So, P₄t = mL
m = P₄t/L
= 777.92 W × 86400 s/333.7 × 10³ J/kg
= 67212288/333.7 × 10³
= 201.42 kg
g Consider the following observations on shear strength (MPa) of a joint bonded in a particular manner. 22.6 40.4 16.4 72.4 36.6 109.8 30.0 4.4 33.1 66.7 81.5 (a) What are the values of the fourths