Heat transfer from a transistor may be enhanced by
inserting it in an aluminium sleeve (k = 200 W/m −
K) having integrally machined longitudinal fins on its
outer surface. Transistor radius and height are r1 =
2 mm & H = 6 mm respectively, while the fins are of
length L = r3 − r2 = 10 mm of uniform thickness t =
0.7 mm. The thickness of the sleeve base is r2 − r1 =
1 mm. Contact resistance of the sleeve transistor
interface is Rt,c
′′ = 10−3 m2
.K/W. Air at T∞ = 20°C
flows over the fin surface providing uniform
convection with h = 25 W
m2−K
. Assume 1-D radial heat
transfer,
a) Sketch the equivalent thermal circuit for heat
transfer from transistor case (r = r1) to the air.
Label each resistance. [1]
b) Evaluate each resistance. [2]
c) If the temperature of the transistor case is T1 = 80 °C, what is the rate of heat transfer from
the sleeve?
Answer:
Heat transfer from a transistor may be enhanced by
inserting it in an aluminium sleeve (k = 200 W/m −
K) having integrally machined longitudinal fins on its
outer surface. Transistor radius and height are r1 =
2 mm & H = 6 mm respectively, while the fins are of
length L = r3 − r2 = 10 mm of uniform thickness t =
0.7 mm. The thickness of the sleeve base is r2 − r1 =
1 mm. Contact resistance of the sleeve transistor
interface is Rt,c
′′ = 10−3 m2
.K/W. Air at T∞ = 20°C
flows over the fin surface providing uniform
convection with h = 25 W
m2−K
. Assume 1-D radial heat
transfer,
Explanation:
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.
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
⇒ [tex]"K" \ of \ Cermet=(K)_{TiC} (V_f)_{TiC}+(K)_{CO} (V_m)_{CO}[/tex]
On putting the given values, we get
⇒ [tex]=(26)(0.76)+(69)(0.24)[/tex]
⇒ [tex]=19.76+16.56[/tex]
⇒ [tex]=36.32 \ W/mk[/tex]
describe how to check vehicle ride height
Answer:
Vehicle manufacturers specify various reference points on the frame, body, fender, bumper or suspension. On some applications, ride height may even be specified as a distance between two points on the vehicle's suspension, such as the distance from the frame rail to the axle or a suspension control arm.
Expression for calories burned during workout
Which of the following wouldn't be pictured on a fan motor's ladder logic diagram? A. Auxiliary contacts B. two Push-button control C. Boiler D. Mixing chamber
Answer:
c
Explanation:
:)
High-mount stop lamps are typically attached to the exterior of the vehicle using:
A. nylon retainers.
B. visible screws.
C. rivets
D. self-locking nuts.
Answer:
Option A
Explanation:
Nylon retainers are knocking screws that have nylon coating on their thread which prevents them from loosening. It generally has two heads Hex Key an star screw. For high mount fixing, star screw is used as it is less prone to stripping. The nylon insert of a Nylock nuts enters into the screw and prevent it from loosening. It is useful in areas where there is high vibration.
Hence, option A is correct
2
2 +
= 0, (0) = 3,
′
(0) = −.
Answer:
the answer is equal to 246890
Users of E85 see a drop in gas mileage because ethanol can't produce the same
amount of energy gasoline can. How much of a drop do they see?
Select one:
a. They see a 10-20% drop in gas mileage
b. The statement is wrong. There is no drop in gas mileage.
c. They see a 30-40% drop in gas mileage
d. They see a 20-30% drop in gas mileage
Answer:
A
Explanation:
Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content.
Describe at least one way you take advantage or could take advantage of each of the different forms of energy
Answer:
Kinetic energy can be used to develop electric energy which can be used as electricity.
Explanation:
The kinetic energy can be harnessed; much like some hydro power technologies harness water movement. A way to convert this kinetic energy into electric energy is through piezoelectric. By applying a mechanical stress to a piezoelectric crystal or material an electric current will be created and can be harvested.
Kinetic energy is also generated by the human body when it is in motion. Studies have also been done using kinetic energy and then converting it to other types of energy, which is then used to power everything from flashlights to radios and more.
Select the correct answer. Which statement best describes a hydrogen fuel cell? A This device uses bioethanol as an additive to power an automobile. B. O C. This device uses photovoltaic cells to capture solar energy and generate electrical energy from it. This device uses fossil fuels to generate heat energy that machines can then convert into mechanical energy. This device converts the chemical energy of hydrogen into electricity through a chemical reaction with oxygen or another oxidizing agent. O D. E. This device converts the kinetic energy of an electric turbine into electricity based on Faraday's law.
Answer:
Explanation:
The correct answer is "D. This device converts the chemical energy of hydrogen into electricity through a chemical reaction with oxygen or another oxidizing agent."
A talks about bio-ethanol fuel.
B is solar.
C is fossil.
E is electricity generation.
Answer:
Explanation:
ans is:
This device converts the chemical energy of hydrogen into electricity through a chemical reaction with oxygen or another oxidizing agent. O D
La Patrulla Fronteriza de los Estados Unidos analiza la compra de un helicóptero nuevo para la vigilancia aérea de la frontera de Nuevo México y Texas con la República Mexicana. Hace 4 años se adquirió un helicóptero similar con un costo de $ 140,000.00. con una tasa de interés de 7% anual. Calcula el factor de pago único y el factor valor presente con los datos anteriores con la tabla y fórmula. Dibuja el diagrama de flujo.
Answer:
The Border Patrol of the United States analyzes the purchase of a new helicopter for the aerial surveillance of the border of New Mexico and Texas with the Mexican Republic. 4 years ago a similar helicopter was purchased at a cost of $ 140,000.00. with an interest rate of 7% per year. Calculate the single payment factor and the present value factor with the above data with the table and formula. Draw the flow chart.
Explanation:
is a water proof material used around tubs and
showers.
A. Cement board
B. Backing board
C. Hard board
D. Finish board
Answer:
hard bored
Explanation:
it seems like it could be either but I think hard bored
Explain the importance of wearing appropriate protective clothing and equipment (PPE), and keeping the work area safe and tidy
Answer:
The wearing of appropriate protective clothing and equipment (PPE) and the keeping of the work area safe and tidy achieve the following for the employees and employers: safety from physical and biological harm that may occur as a result of their contact with the work environment; reduces the cost of insurance and other risk management activities.
Explanation:
The personal protective equipment (PPE) is a safety equipment that protects workers from health or safety risks at their various workplaces. The main purpose is to reduce the workers' exposure to environmental hazards. PPE reduces accidents, improves the health of workers, and reduces the spread of contagious diseases. Above all, it creates safe, secure, and healthy work environments for all.
The electron concentration in silicon at T = 300 K is given by
n(x) = 10^16exp(-x/18) cm^-3
where x is measured in μm and is limited to 0 ≤ x ≤ 25 μm. The electron diffusion coefficient is Dn = 25 cm2/s and the electron mobility is μn = 960 cm2/V-s. The total electron current density through the semiconductor is constant and equal to Jn = -40 A/cm2. The electron current has both diffusion and drift current components. Determine the electric field as a function of x which must exist in the semiconductor.
Answer:
[tex]E=1.44*10^-7-2.6exp(\frac{-x}{18} )v/m[/tex]
Explanation:
From the question we are told that:
Temperature of silicon [tex]T=300k[/tex]
Electron concentration [tex]n(x)=10^{16}\exp (\frac{-x}{18})[/tex]
[tex]\frac{dn}{dx}=(10^{16} *(\frac{-1}{16})\exp\frac{-x}{16})[/tex]
Electron diffusion coefficient is [tex]Dn = 25cm^2/s \approx 2.5*10^{-3}[/tex]
Electron mobility is [tex]\mu n = 960 cm^2/V-s \approx0.096m/V[/tex]
Electron current density [tex]Jn = -40 A/cm^2 \approx -40*10^{4}A/m^2[/tex]
Generally the equation for the semiconductor is mathematically given by
[tex]Jn=qb_n\frac{dn}{dx}+nq \mu E[/tex]
Therefore
[tex]-40*10^{4}=1.6*10^{-19} *(2.5*10^{-3})*(10^{16} *(\frac{-1}{16})\exp\frac{-x}{16})+(10^{16}\exp (\frac{-x}{18}))*1.6*10^{-19}*0.096* E[/tex]
[tex]E=\frac{-2.5*10^-^7 exp(\frac{-x}{18})+40*10^{4}}{1.536*10^-4exp(\frac{-x}{18} )}[/tex]
[tex]E=1.44*10^-7-2.6exp(\frac{-x}{18} )v/m[/tex]
An Otto cycle takes in air at a temperature of 20°C and a pressure of 100 kPa. The high temperature is 1000°C and the compression ratio is 8. The specific heat for air at constant pressure is 1.00 kJ/kg K, and the specific heat for air at constant volume is 0.716 kJ/kg-K. The mass of air in a cylinder is 0.002 kg. If the specific heats stay constant, the clearance volume is most nearly :________
(A) 90 cm
(B) 120 cm3
(C) 180 cm
(D) 210 cm
Which type of hybrid vehicle is propelled by only an electric motor and does not require a traditional transmission to drive the wheels
Answer:
Dual-Mode Hybrid
Explanation:
The type of hybrid vehicle propelled by only an electric motor and does not require a traditional transmission to drive the wheels is known as "DUAL-MODE HYBRID."
Dual-Mode Hybrid is a type of Hybrid Electric Vehicle (HEV) which contains a separate generator consisting of rechargeable batteries. The engine ensures the wheels and the generator are moved; thereby, the electric motor and the batteries are fully powered.
A good example is a Toyota Prius, where during driving conditions, only the electric motor drives the wheels, in which the batteries supply the car with power.
This String method removes beginning and ending spaces of the given string.
Solactone
Answer:
The trim() method will remove both leading and trailing whitespace from a string and return the result. The original string will remain unchanged. If there is no leading or trailing whitespace to be removed, the original string is returned. Both spaces and tab characters will be removed.
This is very useful when comparing user input with existing data. A programmer often racks his brain for hours trying to figure out why what he enters is not the same as a stored string, only to find out that the difference is only a trailing space. Trimming data prior to comparison will eliminate this problem.
Answer:
String result = str. trim(); The trim() method will remove both leading and trailing whitespace from a string and return the result.
Explanation:
what is Auto Cad? and some should help me the drawing of it?
What is Auto Cad?
Answer : AutoCAD is a commercial computer-aided design (CAD) and drafting software application. Developed and marketed by Autodesk, AutoCAD was first released in December 1982 as a desktop app running on microcomputers with internal graphics controllers.
This is the Answer for your question :3
I hope you are having a great day ❤️❤️❤️❤️❤️
Sarah and Raj take/takes me to a baseball game every year.
Either the Cubs or the Orioles play/plays the Yankees tonight.
There is/are nine players on a baseball team.
The home team sit/sits in the dugout on the third-base side of the field.
One of the players called the catcher crouch/crouches behind home plate
I learned how to play soccer from my sister.
Last year, I bought myself season tickets to the local team’s matches.
Only the goalie can use their hands to catch the ball.
The players must quickly move the ball down the field.
This year, my sister gave me my favorite player’s jersey for Christmas.
Answer:
take
play
are
sits
crouches
direct
indirect
direct
direct
indirect
Explanation:
i had just taken the test
anyone down to trade brainiest for points
Refrigerant-134a enters the expansion valve of a refrigeration system at 120 psia as a saturated liquid and leaves at 20 psia. Determine the temperature and internal energy changes across the valve. Use data from the steam tables.
Solution :
[tex]$P_1 = 120 \ psia$[/tex]
[tex]$P_2 = 20 \ psia$[/tex]
Using the data table for refrigerant-134a at P = 120 psia
[tex]$h_1=h_f=40.8365 \ Btu/lbm$[/tex]
[tex]$u_1=u_f=40.5485 \ Btu/lbm$[/tex]
[tex]$T_{sat}=87.745^\circ F$[/tex]
∴ [tex]$h_2=h_1=40.8365 \ Btu/lbm$[/tex]
For pressure, P = 20 psia
[tex]$h_{2f} = 11.445 \ Btu/lbm$[/tex]
[tex]$h_{2g} = 102.73 \ Btu/lbm$[/tex]
[tex]$u_{2f} = 11.401 \ Btu/lbm$[/tex]
[tex]$u_{2g} = 94.3 \ Btu/lbm$[/tex]
[tex]$T_2=T_{sat}=-2.43^\circ F$[/tex]
Change in temperature, [tex]$\Delta T = T_2-T_1$[/tex]
[tex]$\Delta T = -2.43-87.745$[/tex]
[tex]$\Delta T=-90.175^\circ F$[/tex]
Now we find the quality,
[tex]$h_2=h_f+x_2(h_g-h_f)$[/tex]
[tex]$40.8365=11.445+x_2(91.282)$[/tex]
[tex]$x_2=0.32198$[/tex]
The final energy,
[tex]$u_2=u_f+x_2.u_{fg}$[/tex]
[tex]$=11.401+0.32198(82.898)$[/tex]
[tex]$=38.09297 \ Btu/lbm$[/tex]
Change in internal energy
[tex]$\Delta u= u_2-u_1$[/tex]
= 38.09297-40.5485
= -2.4556
Serratia marcescens bacteria are used for the production of threonine. The maximum specific oxygen uptake rate of S. marcescens in batch culture is 4 mmol O2 g-1 h-1. It is planned to operate the fermenter to achieve a maximum cell density of 50 g l-1. At the fermentation temperature and pressure, the solubility of oxygen in the culture liquid is 8 × 10^-3 kg m^-3. The concentration of oxygen in the culture liquid is 0.5 × 10^-3 kg m^-3. At a particular stirrer speed, kLa is 0.17 s^-1.
Required:
Under these conditions, will the rate of cell metabolism be limited by mass transfer?
Answer:
The rate of cell metabolism is limited by mass transfer since the value of maximum cell concentration obtained (38 g/l) is lower than 50 g l-1, the value planed.
Explanation:
Data
kLa = 0.17/s
Solubility of oxygen = 8 × 10^-3 kg / m^3
The maximum specific oxygen uptake rate = 4 mmol O2 / g h.
Concentration of oxygen = 0.5 × 10^-3 kg/ m^3
**The maximum cell density = 50 g/l
___________________
The calculated maximum cell concentration:
xmax= kLa · CAL*/ qo
CAL* is the solubility of oxygen in the broth and qo is the specific oxygen uptake rate
Replacing the data given
xmax= ( 0.17/s ) · (8 × 10^-3 kg / m^3) / 4 mmol O2 / g h
4 mmol O2 / g h to kg O2/ g s
[tex]4 \frac{mmol}{gh} \frac{1 gmol}{1000mmol}\frac{1h}{3600s}\frac{32 g}{gmol} \frac{1Kg}{1000g}[/tex]
= 3.56 x 10^-3 kg O2/ g s
So then,
xmax= ( 0.17/s ) · (8 × 10^-3 kg / m^3) / 3.56 x 10^-3 o kg O2/ g s
xmax= 3. 8 x 10^4 g/ m^3 = 38 g/l
_____________________
A venture tube is used to measure the flow rate of a liquid in a pipe (liquid density is 800 kg/m3). The pipe has a diameter of 10 cm and the smallest diameter of the venture has a diameter of 4 cm. A manometer with a manometer fluid of mercury (specific weight of 133 kN/m3) is used to calculate the flow rate which is connected to the venture section such that one leg is far upstream and the second leg is at the minimum diameter of the venture tube. If the flow rate is 0.05 m3/s determine the elevation change in the manometer fluid.
a. 14.6 m
b. 9.28 m
c. 4.64 m
d. 2.32 m
Answer:
[tex]\triangle h=4.935m[/tex]
Explanation:
From the question we are told that:
Liquid density [tex]\rho=800[/tex]
Diameter of pipe [tex]d=4cm \approx 0.004m[/tex]
Diameter of venture [tex]d=10cm \approx 0.010m[/tex]
Specific weight of mercury P_mg [tex]133 kN/m^3[/tex]
Flow rate [tex]r=0.05 m^3/s[/tex]
Area A:
[tex]A_1=\frac{\pi}{4}0.1^2\\A_1=0.00785m^2\\A_2=\frac{\pi}{4}0.04^2\\A_2=0.001256m^2\\[/tex]
Generally the Bernoulli's equation is mathematically given by
[tex]\frac{P_1}{\rho_1g}+\frac{V_1^2}{2g}=\frac{P_2}{\rho g}+\frac{V_2^2}{2g}\\[/tex]
Where
[tex]V_1=\frac{r}{A_1} \\\\ &V_1=\frac{r}{A_2}[/tex]
Therefore
[tex]P_1-P_2=\frac{Pr^2}{2}(\frac{A_1^2-A_2^2}{A_1^2A_2^2})[/tex]
Generally the equation for pressure difference b/w manometer fluid is given as
[tex]P_1-P_2=(p_mg-pg)\triangle h[/tex]
Therefore
[tex](p_mg-pg)\triangle h=\frac{Pr^2}{2}(\frac{A_1^2-A_2^2}{A_1^2A_2^2})[/tex]
[tex]\triangle h=\frac{\frac{Pr^2}{2}(\frac{A_1^2-A_2^2}{A_1^2A_2^2})}{(p_mg-pg)}[/tex]
[tex]\triangle h=\frac{\frac{(800)(0.05)^2}{2}(\frac{(0.1)^2-(0.4)^2}{(0.1)^2(0.04)^2})}{(1.33*10^3-800*9.81)}[/tex]
[tex]\triangle h=4.935m[/tex]
Therefore elevation change is mathematically given by
[tex]\triangle h=4.935m[/tex]
A continuous and aligned hybrid composite consists of aramid and glass fibers embedded within a polymer resin matrix. Compute the longitudinal modulus of elasticity of this material if the respective volume fractions of the aramid and glass fibers are 0.24 and 0.28, given the following data:
Material Modulus of Elasticity (GPa)
Polyester 2.5
Aramid fibers 131
Glass fibers 72.5
(A) 5.06 GPa
(B) 32.6 GPa
(C) 52.9 GPa
(D) 131 GPa
Answer:
probably b but not sure
Explanation:
The longitudinal modulus of elasticity of this material if the respective volume fractions of the aramid and glass fibers are 0.24 and 0.28, given the following data is 32.6 GPa.
What is elasticity?Elasticity is defined as after the forces producing the deformation are eliminated, a material body that has been distorted has the ability to revert to its original size and shape. Metals' atomic lattices undergo size and form changes when forces are applied. When forces are removed, the lattice returns to its initial, lower energy condition. Rubbers and other polymers are elastic because stretching of polymer chains occurs when forces are applied.
Longitudinal modulus are defined as the proportion of a material's length change caused by applied force to its initial length. Young's modulus is a measurement of a material's capacity to endure changes in length when subjected to compression or tension along its length.
Thus, the longitudinal modulus of elasticity of this material if the respective volume fractions of the aramid and glass fibers are 0.24 and 0.28, given the following data is 32.6 GPa.
To learn more about elasticity, refer to the link below:
https://brainly.com/question/28790459
#SPJ6
State as many general factors as you can think of that influence the design of engineered and manufactured products
Answer:
General Factors that Influence the Design of Engineered and Manufactured Products include:
1. Customer requirements
2. Simple operations with inbuilt facilities
3. Customer satisfaction and intended functionality
4. Cost-effectiveness
5. Quality and conformity with impressive designs
6. Good knowledge of the quality of materials used
7. Product packaging
Explanation:
The factors that influence product designs are numerous. The main purposes of a product design are to maintain attractiveness, functionality, and cost-effectiveness. Therefore, a designer must be innovative and ensure ergonomic designs that meet the user's requirements.
g A 12,000 m3/day treatment plant has a rectangular sedimentation basin with dimensions 12 meters wide, 3 meters deep, and 25 meters long. Will particles with a settling velocity of 6 x 10-3 m/s be removed in this basin
Answer:
The settling velocity of the particles (Vs) is greater than the overflow rate (V₀), thus the particles will settle out and will be removed.
Explanation:
Given;
volumetric flow rate of the treatment, Q₀ = 12,000 m³/day
length of the rectangular tank, L = 25 m
width of the tank, W = 12 m
height of the tank, H = 3 m
settling velocity of the particles, [tex]V_s[/tex] = 6 x 10⁻³ m/s
The overflow rate of the sediments are calculated as follows;
[tex]V_o = \frac{Q_o}{A_s}[/tex]
where;
As is the surface area of the tank, m²
Q₀ is the flow rate, m³/s
As = 2LW + 2LH + 2WH
As = (2 x 25 x 12) + (2 x 25 x 3) + (2 x 12 x 3)
As = 822 m²
[tex]Q_0 (m^3/s)= \frac{12,000 \ m^3}{day} \times \frac{1 \ day}{24 \ hr} \times \frac{1 \ hour}{60 \ \min} \times \frac{1 \ \min}{60 \ s} = \frac{12,000}{24 \times 60 \times 60} (m^3/s)= \frac{12,000}{86,400} \ m^3/s\\\\Q_o = 0.139 \ m^3/s[/tex]
The overflow rate;
[tex]V_o = \frac{Q_0}{A_s} = \frac{0.139}{822} = 1.69 \times 10^{-4} \ m/s[/tex]
The settling velocity of the particles (Vs) is greater than the overflow rate (V₀), thus the particles will settle out and will be removed.
unitate de masura in SI pt F
Answer:
Electrical Capacitance
Explanation:
To find - unit of measure in SI for F
Solution -
The answer is - Electrical Capacitance
Reason -
The farad (symbol: F) is the SI derived unit of electrical capacitance, the ability of a body to store an electrical charge.
Răspuns:
Capacitate electrică
Explicaţie:
Pentru a găsi - unitate de măsură în SI pentru F
Soluție -
Răspunsul este - Capacitate electrică
Motiv -
Farada (simbolul: F) este unitatea de capacitate electrică derivată din SI, capacitatea unui corp de a stoca o sarcină electrică.