How will the new table column names be created? How can you change the column names: O SELECT *
INTO newtable [IN externaldb]
FROM table1;
O SELECT *
INTO CustomersBackup2013 IN 'Backup.mdb'
FROM Customers;
O SELECT CustomerName, ContactName
INTO CustomersBackup2013
FROM Customers;
O The new table will be created with the column-names and types as defined in the SELECT statement. You can apply new names using the AS clause.
Answers
When creating a new table using the SELECT statement in SQL, the new table column names will be created based on the column-names and types as defined in the SELECT statement.
However, you can change the column names by using the AS clause to apply new names. For example, in the third option provided, the column names for the new table "CustomersBackup2013" will be "CustomerName" and "ContactName" as defined in the SELECT statement. But if you want to change those column names, you can use the AS clause as follows:
SELECT CustomerName AS Name, ContactName AS Contact
INTO CustomersBackup2013
FROM Customers;
This will create a new table "CustomersBackup2013" with column names "Name" and "Contact" instead of "CustomerName" and "ContactName". Additionally, if you want to create a new table in an external database, you can specify the database name in the IN clause, as shown in the second option provided.
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Related Questions
Hi can you help me pls?
Answers
Choose the option to correctly complete the following sentence. To insert a column in a worksheet, you should a.click the line dividing the columns between which you want to insert the column and drag the line to the right b.double-click the column header (A,B,C, etc.). c.click the column header (A,B,C, etc.), then Insert, then Columns. d.click Format, then Column, then Autoformat Selection.
Answers
Click Columns, then Insert, then the desired column heading (A, B, C, etc.). This is the proper way to add a new column to an Excel worksheet. by clicking on the rightmost column's column header.
How do I create a column in Excel between columns B and C?To add a single column, simply right-click the entire column to the right of the desired location and choose Insert Columns. To add several columns: To the right of where you wish to add new columns, choose the same amount of columns.
What does an Excel column header mean?In essence, column headers describe the category to which the data in that column belongs. For illustration, if column A.
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Which of the following statements is false with regards to intermodal transportation? Select one: A. Cargo travels under one carrier contact B. Cargo travels under multiple carrier contracts C. Cargo travels over various modes D. Cargo always moves in a container
Answers
The false statement with regards to intermodal transportation is "Cargo always moves in a container."
Intermodal transportation is a method of transporting goods using two or more modes of transportation, such as rail, truck, or ship. When goods are transported using intermodal transportation, the goods are moved in a container or trailer, and the container or trailer is transferred between modes of transportation, such as from a ship to a train or from a train to a truck.Intermodal transportation's key featuresIntermodal transportation offers several advantages over other modes of transportation, including its flexibility and cost-effectiveness. Here are some of the key features of intermodal transportation:Efficiency: Intermodal transportation allows for the efficient transfer of goods from one mode of transportation to another. For example, a truck may transport a container to a rail yard, where the container is transferred to a train for long-distance transport.Cost-effectiveness: Intermodal transportation can be less expensive than other modes of transportation because it takes advantage of the strengths of each mode. For example, rail is often less expensive than truck transport for long-distance shipments, but trucking is faster and more flexible than rail transport.Flexibility: Intermodal transportation allows for greater flexibility in shipping goods. For example, a shipper can choose to transport goods via truck, rail, or ship, depending on the specific needs of the shipment and the destination.False statement with regards to intermodal transportation: "Cargo always moves in a container." The statement is incorrect because while containers are commonly used in intermodal transportation, cargo can be transported in other ways, such as trailers.
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Which personal protective equipment (PPE) should you wear when working around asbestos-containing materials?
A) Respiratory protectionB) Protective work clothing, including gloves C) Face shields and/or vented goggles D) All of the above
Answers
Answer:
d
Explanation:
yea
Answer:
D
Explanation:
under what conditions would a waterways conservation officer instruct a vessel operator to return to the nearest mooring
Answers
A Waterways Conservation Officer is responsible for preserving and protecting aquatic life and the environment. They make sure that vessels and operators comply with laws, regulations, and policies related to waterways conservation and management.
In some cases, they may instruct vessel operators to return to the nearest mooring. Some conditions that may lead to such instruction include:1. Inclement Weather:In bad weather conditions, such as heavy storms, winds, or thunderstorms, a Waterways Conservation Officer may instruct a vessel operator to return to the nearest mooring. This is because operating a vessel in such conditions can be risky, dangerous, and potentially life-threatening.
2. Safety Concerns:If a vessel operator is not following the safety rules and regulations, a Waterways Conservation Officer may instruct them to return to the nearest mooring. This may include cases where the vessel is overloaded, not carrying enough life jackets, or the operator is not wearing a personal flotation device.3. Breaking Laws:If the vessel operator is breaking any waterways laws or regulations, the Waterways Conservation Officer may instruct them to return to the nearest mooring.
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Explain in details what limiting function friction is and Cone
Answers
Cone of friction refers to a cone where the resulting force exerted by one flat horizontal surface on another is to be located while both surfaces are at rest and determined by the coefficient of static friction.
What is Static friction?The resistance to motion of one object moving in relation to another is known as friction. It is not regarded as a fundamental force like gravity or electromagnetic, according to the International Journal of Parallel, Emergent and Distributed Systems(opens in new tab).
The electromagnetic attraction between charged particles in two contacting surfaces, according to scientists, is what causes it.
According to the book Soil Mechanics(opens in new tab), scientists started putting together the laws governing friction in the 1400s.
Therefore, Cone of friction refers to a cone where the resulting force exerted by one flat horizontal surface on another is to be located while both surfaces are at rest and determined by the coefficient of static friction.
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Set up the following characteristic equations in the form suited to Evanss root-locus method. Give L(s), a(s), and b(s) and the parameter, K, in terms of the original parameters in each case. Be sure to select K so that a(s) and b(s) are monic in each case and the degree of b(s) is not greater than that of a(s).
a) s + (1/τ) = 0 versus parameter τ
b) s2 + cs + c + 1 = 0 versus parameter c
c) (s + c)3 + A(Ts + 1) = 0
i. versus parameter A
ii. versus parameter T
iii. versus the parameter c, if possible. Say why you can or can not. Can a plot of the roots be drawn versus c for given constant values of A and T by any means at all.
d) 1 + (kp + k1/s + kDs/Ts + 1)G(s) = 0. Assume that G(s) = A c(s)/d(s), where c(s) and d(s) are monic polynomials with the degree of d(s) greater than that of c(s).
i. versus kp
ii. versus kI
iii. versus kD
iv. versus τ
Answers
Answer:
attached below is the detailed solution and answers
Explanation:
Attached below is the detailed solution
C(iii) : versus the parameter C
The parameter C is centered in a nonlinear equation, therefore the standard locus will not apply hence when you use a polynomial solver the roots gotten would be plotted against C
Answer: a(s) is of degree n and b(s) is of degree n-1.
a)Characteristic equation in form suitable for Evans's root-locus method is given by a(s) + b(s)K = 0, where a(s) and b(s) are polynomials of s with real coefficients. Now, given equation can be represented as: s + (1/τ) = 0 => s + (1/τ) = 0s + (1/τ)K = 0=> K = -τs/τ + 0Thus, L(s) = s, a(s) = 1, b(s) = 1 and K = -τ.
b)The characteristic equation is given by:s^2 + cs + c + 1 = 0For the root-locus method, we have to write the characteristic equation in the form a(s) + b(s)K = 0. Since the degree of a(s) is 2, we select K such that the degree of b(s) is also 2, and so b(s) will be monic.s^2 + cs + c + 1 = 0=> (s + c/2)^2 + 1/4 - c^2/4 + c = 0=> s^2 + (2c)s + (1 + c - c^2/4) = 0Now, taking a(s) = s^2 + (2c)s + (1 + c - c^2/4) and b(s) = 1 with K = -1/c^2, we have:a(s) + b(s)K = s^2 + (2c)s + (1 + c - c^2/4) - 1/c^2 = 0
c) The characteristic equation is given by:(s + c)3 + A(Ts + 1) = 0
i. versus parameter A:s = -c is a repeated root of multiplicity 3 when A = 0For s = -c, the characteristic equation becomes:-A(Tc + 1) = 0If A = 0, the characteristic equation will be (s + c)^3 = 0 and will have a repeated root at s = -c with a multiplicity of 3.
ii. versus parameter T:s = -c is a repeated root of multiplicity 3 when T = 0.For s = -c, the characteristic equation becomes:3c^2s + A = 0If A = 0, the characteristic equation will be (s + c)^3 = 0 and will have a repeated root at s = -c with a multiplicity of 3.
iii. versus the parameter c:We cannot draw the root locus of (s + c)3 + A(Ts + 1) = 0 with respect to the parameter c because there is no c term in the characteristic equation; it only contains c cubed.
d) The characteristic equation is given by:1 + (kp + k1/s + kDs/Ts + 1)G(s) = 0Assuming G(s) = Ac(s)/d(s), where c(s) and d(s) are monic polynomials with the degree of d(s) greater than that of c(s), the characteristic equation becomes:
d(s) + kp d(s) + k1 d(s)/s + kDs c(s)/T = 0.
Thus, a(s) = d(s) + k1 d(s)/s and b(s) = kDc(s)/T + kp d(s) with K = -1.
Therefore, a(s) is of degree n and b(s) is of degree n-1.
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A shaft of a circular cross section is supported by two housings at B and C. The shaft
is subjected to static loads: concentrated force N applied by gear D and an applied torque T. The yielding strength of the shaft is Sy, and the diameter of the shaft is d. For circular cross sections, | = nd*/64, J = md*/32. The length of the shaft is L. Transverse shear stress is ignored here.
1) Draw the bending moment diagram of the shaft. Specify the location of the weakest (most dangerous) cross section A on bending moment diagram.
2) Draw the weakest point(s) on cross section A.
3) Determine the von-Mises stress at the weakest point(s).
4) Determine the factor of safety n based on Distortion Energy Theory.
Answers
Answer:
1) The bending moment diagram of the shaft is shown in Figure 1. The weakest cross section A is located at the point where the bending moment is maximum.
2) The weakest point on cross section A is located at the point where the bending moment is maximum.
3) The von-Mises stress at the weakest point is given by:
σ = M/I
where M is the bending moment and I is the moment of inertia of the cross section.
4) The factor of safety n is given by:
n = Sy/σ
where Sy is the yield strength of the shaft and σ is the von-Mises stress at the weakest point.
Explanation:
Hope this helps!
What is the impedance of an ideal parallel resonant circuit (no resistance in either branch)?
Answers
Answer:
infinite
Explanation:
The impedance of an ideal parallel resonant circuit is infinite at the resonant frequency. The sum of the admittances of the branches of the circuit is zero.
Explain what happened to the pump rate when you increased the stroke volume. Why do you think this occurred
Answers
Answer:
Increase in stroke volume brings about increase in pump rate .the relationship between them is linearly proportional.
Explanation:
Increase in stroke volume brings about increase in pump rate .the relationship between them is linearly proportional.
The rate at which blood is been pumped by the heart depends on the Stroke volume as well as heart rate. The stroke volume gives the quantity of blood that is been pumped by the heart Everytime it beats.
One of the important factor that determine the Cardiac output is Stroke volume. And injection fraction is calculated as (stroke volume/
end-diastolic volume)
In developing engine designs, manufacturers use thermocouples to measure the ___________ of components, such as spark plugs and exhaust systems.
Answers
Answer: High temperatures
The maximum voltage in a cooling system should not exceed ______ volts.
Answers
Answer:2%
When the voltages between the three phases are not equal, the current increases dramatically in the motor winding's, and if allowed to continue, the motor will be damaged.
Explanation:
An Otto cycle with air as the working fluid has a compression ratio of 8.2. Under cold air standard conditions, what is the thermal efficiency of this cycle?
Answers
Answer:
Under cold air standard conditions, the thermal efficiency of this cycle is 56.9 percent.
Explanation:
From Thermodynamics we remember that thermal efficiency of the ideal Otto cycle (\(\eta_{th}\)), dimensionless, is defined by the following formula:
\(\eta_{th} = 1-\frac{1}{r^{\gamma-1}}\) (Eq. 1)
Where:
\(r\) - Compression ratio, dimensionless.
\(\gamma\) - Specific heat ratio, dimensionless.
Please notice that specific heat ratio under cold air standard conditions is \(\gamma = 1.4\).
If we know that \(r = 8.2\) and \(\gamma = 1.4\), then thermal efficiency of the ideal Otto cycle is:
\(\eta_{th} = 1-\frac{1}{8.2^{1.4-1}}\)
\(\eta_{th} = 0.569\)
Under cold air standard conditions, the thermal efficiency of this cycle is 56.9 percent.
A large truck drives down the highway at 10 m/s hauling a rectangular trailer that is 6 m long, 2 m wide, and 2 m tall. The trailer contains frozen food and is therefore temperature-controlled. Its external surface can be approximated to be a consistent 15°C, while the outside air is at 20°C. Assume the heat transfer on the front, back, and bottom of the trailer is negligible.
a) How much cooling power must be provided to maintain the temperature controlled trailer? (i.e. What is the total heat transfer rate from the air to the trailer)?b) What is the minimum local heat transfer coefficient on the surface of the trailer? Where does the minimum occur?c) What percentage of the total heat transfer is occuring over a laminar boundary layer?d) If the cooling system can only provide 5 KW of cooling, what is the fastest speed that this truck can drive while still adequately maintaining the temperature within the trailer?
Answers
Answer:
3w/m²k
Explanation:
Base on the scenario been described in the question, the solution to the given problem solve in the file attached below
Estimate the maximum expected thermal conductivity for a Cermet that contains 58 vol% titanium carbide (TiC) particles in a cobalt matrix. Assume thermal conductivities of 27 and 69 W/m-K for TiC and Co respectively.
Answers
Answer:
The right answer is "36.32 W/mk".
Explanation:
According to the question,
TiC = 76%
or,
= 0.76
CO = 24%
or,
= 0.24
Thermal conductivity of TiC,
= 26 W/mk
Thermal conductivity of CO,
= 69 W/mk
On applying the rule, we get
⇒ \("K" \ of \ Cermet=(K)_{TiC} (V_f)_{TiC}+(K)_{CO} (V_m)_{CO}\)
On putting the given values, we get
⇒ \(=(26)(0.76)+(69)(0.24)\)
⇒ \(=19.76+16.56\)
⇒ \(=36.32 \ W/mk\)
The gross weight of a two-place Piper Cherokee is 2000lb and its wing area is 160 ft^2. What is its wing loading
Answers
Answer:
\(W = 12.5\ lb/ft^2\) --- in \(lb/ft^2\)
\(W = 598.503N/m^2\) --- in \(N/m^2\)
Explanation:
Given
\(Weight=2000lb\)
\(Area = 160ft^2\)
Required
Determine the wing loading (W)
Wing loading is calculated using:
\(W = \frac{Weight}{Area}\)
Substitute values for Weight and Area
\(W = \frac{2000lb}{160ft^2}\)
\(W = 12.5\ lb/ft^2\)
The answer can also be converted to N/m^2
\(1\ lb = 4.4482216153N\)
\(1ft^2 = 0.092903m^2\)
So, we have:
\(W = \frac{12.5 * 4.4482216153N}{0.092903m^2}\)
\(W = \frac{55.6027701912N}{0.092903m^2}\)
\(W = 598.503N/m^2\)
Hence, the wing loading is:
\(W = 12.5\ lb/ft^2\) --- in \(lb/ft^2\)
\(W = 598.503N/m^2\) --- in \(N/m^2\)
Given that s has been defined, and that the_set that refers to a set, write an expression that whose value is True if and only if the value to which s refers is in the_set.
Answers
If the value to which s refers is in the set the_set, the following expression will evaluate to True:
s in the_set
This expression uses the in keyword to check if the value of s is contained in the set the_set. If the value of s is in the set, the expression will evaluate to True, and if the value is not in the set, the expression will evaluate to False.
Which of the following can cause a flopping sound at the front of the engine
A) drive belt too loose
B) timing chain too loose
C) drive belt too tight
D) timing chain too tight
Answers
An organization sets its standards for quality according to the best product it can produce.
True
False
Answers
Answer:
True!! took the test
Explanation:
develop a note on important alloys
Answers
Alloys are mixtures of two or more metals, or a metal and a non-metal, that are created to enhance the properties of the individual metals. Alloys are used in a wide range of applications, from construction to electronics to transportation, and are essential to modern technology and industry.
Some important alloys include:
Steel: Steel is an alloy of iron and carbon, with small amounts of other elements such as manganese, silicon, and sulfur. Steel is strong, durable, and versatile, and is used in a wide range of applications, from construction to manufacturing to transportation.
Brass: Brass is an alloy of copper and zinc, with small amounts of other elements such as lead or tin. Brass is valued for its corrosion resistance, low friction, and attractive appearance, and is used in applications such as plumbing fixtures, musical instruments, and decorative items.
Bronze: Bronze is an alloy of copper and tin, with small amounts of other metals such as aluminum, silicon, or phosphorus. Bronze is strong, durable, and corrosion-resistant, and is used in applications such as sculptures, coins, and bearings.
Stainless steel: Stainless steel is an alloy of iron, chromium, and nickel, with small amounts of other metals such as molybdenum or titanium. Stainless steel is highly resistant to corrosion, heat, and wear, and is used in applications such as cutlery, medical equipment, and aerospace components.
Aluminum alloys: Aluminum alloys aremixtures of aluminum with other metals such as copper, zinc, or magnesium. Aluminum alloys are lightweight, strong, and corrosion-resistant, and are used in a wide range of applications, from aircraft and automobiles to construction and consumer goods.
Titanium alloys: Titanium alloys are mixtures of titanium with other metals such as aluminum, vanadium, or nickel. Titanium alloys are strong, lightweight, and corrosion-resistant, and are used in applications such as aerospace, medical implants, and sports equipment.
Nickel-based alloys: Nickel-based alloys are mixtures of nickel with other metals such as chromium, iron, or cobalt. Nickel-based alloys are heat-resistant, corrosion-resistant, and have high strength and toughness, and are used in applications such as jet engines, chemical processing, and power generation.
Copper-nickel alloys: Copper-nickel alloys are mixtures of copper with nickel and sometimes other metals such as iron or manganese. Copper-nickel alloys are highly resistant to corrosion and have good thermal and electrical conductivity, making them ideal for applications such as marine engineering, heat exchangers, and electrical wiring.
In conclusion, alloys are important materials that are used extensively in modern technology and industry. By combining the properties of different metals, alloys can be tailored to meet specific needs and applications, and have revolutionized the way we design and make things.
Which thematic group is involved in the transmission and generation of electrical power?
a.Communication Systems
b.Control Systems
c.Computer Systems
d.Energy Systems
e.Electronic Systems
Answers
Answer:
The 17 distinct years Mariah Carey has topped Billboard's Hot 100, spanning an historic four consecutive decades:
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2005
2006
2008
2019
2020
2021
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Answers
Answer:
warm fronts:
1. Gentle long lasting rain
2. Half red circles
3. Slides over the top of air masses
cool fronts:
1. Blue triangles
2. Force existing air into atmo
3. Heavy storms
Explanation:
is correct.
increasing voltage above the piv rating . a.will increase forward current b.may destroy the diode c.may destroy the diode because of avalanche current d.will cause avalanche current
Answers
Increasing the voltage applied to a diode above its PIV rating can result in increased forward current, and may lead to the destruction of the diode due to an increase in avalanche current.
A. Increasing the voltage applied to a diode above its PIV rating will increase the forward current, or current flowing through the diode when it is conducting.
B. The diode may be destroyed because of the increase in current if the current exceeds the maximum ratings for the device.
C. The diode may be destroyed because of the increased current that can occur in the event of an avalanche breakdown. An avalanche breakdown occurs when the current is increased to a certain point and the reverse breakdown voltage of the diode is exceeded. This results in a large increase in the current through the diode, which can cause it to fail.
D. An increase in voltage above the PIV rating may cause an avalanche current. Avalanche current is a phenomenon that occurs in a diode when the reverse breakdown voltage is exceeded, leading to a large increase in current.
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what is the difference between a stepped and a non-stepped ECT circuit?
Answers
Answer:
A stepped circuit is designed in the engine coolant temperature (ECT) sensor within a powertrain control module (PCM) to increase the sensor's accuracy. A simple non-stepped ECT sensor circuit has a specific resistance which increases or decreases according to the changes in engine coolant temperature.
Explanation:
What sub-discipline of Mechanical Engineering focuses
heavily on vehicle design and testing?
Geothermal Engineering
Automotive Engineering
Biomedical Engineering
Architectural Engineering
Answers
Answer:
Automotive engineering
An industrial overhead door has sprocket and chain system designed to reduce the force needed by an operator to open and close the door. the system consists of two individual systems that are connected through a live axle shaft. to operate the door, the operator pulls a continuous loop of chain over a fixed 22-tooth sprocket that is attached to a live axle shaft (system 1). a second 22-tooth sprocket is attached to the live axle shaft and uses a chain connected to a 48-tooth sprocket that is attached to a drum that drives the door.
Answers
The overall system gear ratio is 24 : 11.
The comic strip approximately annotating the power education has been attached.
Gear systems incorporate numerous gears and are the primary additives of many engineering packages along with using trains in cars. In working tools systems, non-easy dynamics along with tools hammering or high-frequency oscillations can also additionally occur.
Gear has the characteristic to switch movement and torque among gadget additives in mechanical devices. Gears can alternate the course of motion and/or beautify the end result pace or torque.
To determine the overall system gear ratio we can use the formula below:
GR = 48 : 22
GR = 24 : 11
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Explain why the phase angle between the generator voltage and the resistor voltage decreases as the frequency is increased?
Answers
At low frequencies, the resistor behaves as a purely resistive element, meaning that the current flowing through it is in phase with the voltage across it. Therefore, the phase angle between the generator voltage and the resistor voltage is 0 degrees.
However, as the frequency of the AC signal increases, the impedance of the resistor becomes more complex, with both resistive and reactive components. The reactive component of the resistor's impedance is proportional to the frequency of the signal, so as the frequency increases, the reactive component becomes more significant.
This reactive component causes the current to lead or lag the voltage, depending on the sign of the reactance. In the case of a purely resistive element, the current leads the voltage by 90 degrees. As the frequency increases, the current leads the voltage by a smaller angle because the reactive component of the resistor's impedance becomes less significant at higher frequencies.
Therefore, the phase angle between the generator voltage and the resistor voltage decreases as the frequency is increased, approaching 0 degrees as the frequency becomes very high.
Answer:
The phase angle between the generator voltage and the resistor voltage in an AC circuit is determined by the relationship between the voltage and the current, as described by Ohm's Law.
At low frequencies, the resistor behaves as a purely resistive element, meaning that the current flowing through it is in phase with the voltage across it. Therefore, the phase angle between the generator voltage and the resistor voltage is 0 degrees.
However, as the frequency of the AC signal increases, the impedance of the resistor becomes more complex, with both resistive and reactive components. The reactive component of the resistor's impedance is proportional to the frequency of the signal, so as the frequency increases, the reactive component becomes more significant.
This reactive component causes the current to lead or lag the voltage, depending on the sign of the reactance. In the case of a purely resistive element, the current leads the voltage by 90 degrees. As the frequency increases, the current leads the voltage by a smaller angle because the reactive component of the resistor's impedance becomes less significant at higher frequencies.
Therefore, the phase angle between the generator voltage and the resistor voltage decreases as the frequency is increased, approaching 0 degrees as the frequency becomes very high.
elivery Execution Knowledge Check Question 1 of 8. When you walk into the station at the end of your route, what should you do? Check in with your DSP and being any undeliverable packages back to the Amazon Retum to Station desk O leave the undeliverable packages with your OSP then go off duty You don't have to return to the station at the end of your day Sign out of your device and love Mark for foto up
Answers
Answer:
ur hhbkiegtbckdj you and your family a very merry merry
1.12 you’ve experienced convection cooling if you’ve ever extended your hand out the window of a moving vehicle or into a flowing water stream. with the surface of your hand at a temperature of 30°c, determine the convection heat flux for (a) a vehicle speed of 40 km/h in air at −8°c with a convection coefficient of 40 w/m2 ⋅k and (b) a velocity of 0.2 m/s in a water stream at 10°c with a convection coefficient of 900 w/m2 ⋅k. which condition would feel colder? contrast these results with a heat flux of approximately 30 w/m2 under normal room conditions.
Answers
To determine the convection heat flux in each scenario, we can use the formula Q = hA(T_surface - T_surrounding), where Q is the heat flux, h is the convection coefficient, A is the surface area, and T_surface and T_surrounding are the temperatures of the surface and the surrounding medium, respectively.
For scenario (a):
- Vehicle speed: 40 km/h
- Air temperature: -8°C
- Surface temperature: 30°C
- Convection coefficient: 40 W/m²·K
First, we need to convert the vehicle speed from km/h to m/s:
40 km/h = (40 * 1000) m / (60 * 60) s ≈ 11.11 m/s
Next, we can calculate the heat flux:
Q = 40 W/m²·K * A * (30°C - (-8°C))
Now, let's move on to scenario (b):
- Water stream velocity: 0.2 m/s
- Water temperature: 10°C
- Surface temperature: 30°C
- Convection coefficient: 900 W/m²·K
For this scenario, we can calculate the heat flux using the same formula:
Q = 900 W/m²·K * A * (30°C - 10°C)
To determine which condition feels colder, we compare the heat flux values. The higher the heat flux, the faster heat is transferred away from the hand, making it feel colder.
Now, let's compare the heat flux values with the approximate heat flux under normal room conditions (30 W/m²):
- If the heat flux is higher than 30 W/m², the condition would feel colder.
- If the heat flux is lower than 30 W/m², the condition would feel warmer.
To find the convection heat flux, we use the formula Q = hA(T_surface - T_surrounding). By calculating the heat flux for each scenario, we can determine which condition would feel colder by comparing the values with the approximate heat flux under normal room conditions.
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For a steel alloy it has been determined that a carburizing heat treatment of 11.3 h duration will raise the carbon concentration to 0.44 wt% at a point 1.8 mm from the surface. Estimate the time necessary to achieve the same concentration at a 4.9 mm position for an identical steel and at the same carburizing temperature.
Answers
This question is incomplete, the complete question is;
For a steel alloy it has been determined that a carburizing heat treatment of 11.3 h duration at Temperature T1 will raise the carbon concentration to 0.44 wt% at a point 1.8 mm from the surface. A separate experiment is performed at T2 that doubles the diffusion coefficient for carbon in steel.
Estimate the time necessary to achieve the same concentration at a 4.9 mm position for an identical steel and at the same carburizing temperature T2.
Answer:
the required time to achieve the same concentration at a 4.9 is 83.733 hrs
Explanation:
Given the data in the question;
treatment time t₁ = 11.3 hours
Carbon concentration = 0.444 wt%
thickness at surface x₁ = 1.8 mm = 0.0018 m
thickness at identical steel x₂ = 4.9 mm = 0.0049 m
Now, Using Fick's second law inform of diffusion
\(x^2\) / Dt = constant
where D is constant
then
\(x^2\) / t = constant
\(x^2_1\) / t₁ = \(x^2_2\) / t₂
\(x^2_1\) t₂ = t₁\(x^2_2\)
t₂ = t₁\(x^2_2\) / \(x^2_1\)
t₂ = (\(x^2_2\) / \(x^2_1\))t₁
t₂ = \((\) \(x_2\) / \(x_1\) \()^2\) × t₁
so we substitute
t₂ = \((\) 0.0049 / 0.0018 \()^2\) × 11.3 hrs
t₂ = 7.41 × 11.3 hrs
t₂ = 83.733 hrs
Therefore, the required time to achieve the same concentration at a 4.9 is 83.733 hrs