A species A diffuses radially outwards from a sphere of radius ro. The following assumptions can be made. The mole fraction of species A at the surface of the sphere is XAO. Species A undergoes equimolar counter-diffusion with another species B. The diffusivity of A in B is denoted DAB. The total molar concentration of the system is c. The mole fraction of A at a radial distance of 10ro from the centre of the sphere is effectively zero. (a) Determine an expression for the molar flux of A at the surface of the sphere under these circumstances. Likewise determine an expression for the molar flow rate of A at the surface of the sphere. [12 marks] (b) Would one expect to see a large change in the molar flux of A if the distance at which the mole fraction had been considered to be effectively zero were located at 100ro from the centre of the sphere instead of 10ro from the centre? Explain your reasoning. [4 marks] (c) The situation described in (b) corresponds to a roughly tenfold increase in the length of the diffusion path. If one were to consider the case of 1-dimensional diffusion across a film rather than the case of radial diffusion from a sphere, how would a tenfold increase in the length of the diffusion path impact on the molar flux obtained in the 1-dimensional system? Hence comment on the differences between spherical radial diffusion and 1-dimensional diffusion in terms of the relative change in molar flux produced by a tenfold increase in the diffusion path.

Answer:

An assessment is the evaluation or estimation of the nature, quality, or ability of someone or something.

Answer:

a) \(h_c = 0.1599 W/m^2-K\)

b) \(H_{loss} = 5.02 W\)

c) \(T_s = 302 K\)

d) \(\dot{Q} = 25.125 W\)

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, \(T_a = 25^0 C = 298 K\)

Pipe length, L = 10 m

Area, A = 2πrL

A = 2π * 0.125 * 10

A = 7.855 m²

Mass flow rate,

\(\dot{ m} = 4.5 tons/hr\\\dot{m} = \frac{4.5*1000}{3600} = 1.25 kg/sec\)

Rate of heat transfer,

\(\dot{Q} = \dot{m} c_p ( T_1 - T_2)\\\dot{Q} = 1.25 * 1.005 * (577 - 557)\\\dot{Q} = 25.125 W\)

a) To calculate the convection coefficient relationship for heat transfer by convection:

\(\dot{Q} = h_c A (T_1 - T_2)\\25.125 = h_c * 7.855 * (577 - 557)\\h_c = 0.1599 W/m^2 - K\)

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, \(k_c = 0.8\)

\(\dot{Q} = k_c A (T_s - T_a)\\25.125 = 0.8 * 7.855 * (T_s - 298)\\T_s = 302 K\)

b) Heat loss from the pipe to the environment:

\(H_{loss} = h_c A(T_s - T_a)\\H_{loss} = 0.1599 * 7.855( 302 - 298)\\H_{loss} = 5.02 W\)

d) The required fan control power is 25.125 W as calculated earlier above

Answer:

0.67 mm

Explanation:

Solution:

We find the dimensionless parameters by applying the critical stress crack propagation formula stated below:

σс= Klc/Y√πa

Y = Klc/σс √πa

σс = this is the critical stress needed for initial cracking propagation

Klc = the plain stress fracture toughness

a = surface length of the crack

Y = the dimensionless parameter

Now, we substitute the values  62MPa√m for Klc, 250 MPa for σс and  1.6 * 10 ^⁻3 for a in the dimensionless parameter equation.

Thus,

Y = Klc/σс √πa

= 62/250(√π * 1.6* 10 ^⁻3)

= 3.492

The next step is to find the maximum permitted surface crack length by applying the  critical stress crack propagation equation given below:

σс= Klc/Y√πa

a= 1/π (Klc/Yσс)²

Now, substitute 40 MPa√m for Klc, 250 MPa for σс and 3.492 for surface length crack  equation

So,

a= 1/π (Klc/Yσс)²

= 1/π[40/3.492 * 250]²

=1/π[40/873]²

=1/π[0.0458]²

0.318[0.0458]²

=0.318[0.00209]

= 0.0066

0.67* 10 ^⁻3 m

= 0.67 mm

Therefore the maximum surface crack length produced is 0.67 mm

The  difference in voltage across the two loads is 6 V.

In a series circuit, the total resistance is equal to the sum of the individual resistances. In this case, the total resistance of the circuit is 2 Ω + 4 Ω = 6 Ω.

The current in a series circuit is the same through all of the loads. This means that the same amount of voltage is dropped across each load. Since the power source has a voltage of 12 V, and the total resistance of the circuit is 6 Ω, the current in the circuit can be calculated using Ohm's Law:

I = V/R

= 12 V / 6 Ω

= 2 A.

Since the same current flows through both loads and the same amount of voltage is dropped across each load, there is no difference in voltage across the two loads. Both loads experience a voltage drop of:

12 V / 2

= 6 V.

Learn more about series circuit from

https://brainly.com/question/24707814
#SPJ1

Answer:

i think its called leggings thats wut my shop teacher told me

Explanation:

An intelligent workplace boosts employees' activities through fluid workflows and the automation of routine job procedures made possible by the Internet of Things (IoT) and artificial intelligence (AI).

The Intelligent Workplace serves as a test bed for evaluating the effectiveness of new procedures and products because it is a working office, research environment, and instructional setting. The Center's research team worked along with Swiss architect Pierre Zoelly to create the project's design.

An intelligent workplace boosts employees' activities through fluid workflows and the automation of routine job procedures made possible by the Internet of Things (IoT) and artificial intelligence (AI).

To know more about artificial intelligence visit:-

https://brainly.com/question/23824028

#SPJ1

Answer:The preferred development environment can vary depending on personal preferences, the type of project, and the programming language being used.

Explanation:

Answer:

it's not included

Explanation:

plz exact ur explain

Answer:

si amor

Explanation:

Hoiykñjdnlklbutrk

Answer:

Technician A is corect

Explanation:

Because he said the correct reason

The flaring tube connection is made with the connection from the copper end of the tube in the nut and fitting. Hence, option A is correct.

Flaring tubes are the tools that are made for the formation of the joining in the two tubes. They are used to make connections or fittings.

The use of a flaring tube is made with the formation of the copper tube to be connected with the nut and the fitting. Thus technician A is correct. Hence, option A is correct.

Learn more about flaring tools, here:

https://brainly.com/question/13610286

#SPJ2

Answer:

b. American Society of Mechanical Engineers

Explanation:

The "American Society of Mechanical Engineers" (ASME) is an organization that ensures the development of engineering fields. It is an accreditation organization that ensures parties will comply to the ASME Boiler and Pressure Vessel Code or BPVC.

The BPVC is a standard being followed by ASME in order to regulate the different pressure vessels and valves. Such standard prevents boiler explosion incidents.

It would need 32 acres of land to produce 1,000 megawatts of power.

Answer:

Deactivated Anti-Lock Braking System

Explanation:

Well this actually depends on the vehicles braking function

I'd say in this case not sure if ABS coz it prevents the vehicle from slipping while braking...

On the otherside ESP is inportant for it stability

Answer:

The development of homosapiens

Explanation:

People adapted to the harsh weather by creating tools and used land bridges to spread to new regions

Answer: So you are dealing with maximum and minimum weights and you want to know what MINIMUM number of supporting strands for this block and tackle system are needed I believe. If so you are dealing with economic imbalances Though we are not worrying about money Right? Right we need physics which Physics study matter and how it moves You would need 8 STRANDS

Explanation: Step By Step

Actions violated:

Actions to be taken:

Edit: Use these to write your paragraph.

Answer:

\($ S_2 - S_1 = -0.1104 \: \: kJ/kg.K$\)

The entropy change of the carbon dioxide is -0.1104 kJ/kg.K

Explanation:

We are given that carbon dioxide undergoes a process in a closed system.

We are asked to find the entropy change of the carbon dioxide  with the assumption that the specific heats are constant.

The entropy change of the carbon dioxide is given by

\($ S_2 - S_1 = C_p \ln (\frac{T_2}{T_1}) - R\ln (\frac{P_2}{P_1}) $\)

Where Cp is the specific heat constant

Cp = 0.846 kJ/kg.K

R is the universal gas constant

R = 0.1889 kJ/kg.K

T₁ and T₂ is the initial and final temperature of carbon dioxide.

P₁ and P₂ is the initial and final pressure of carbon dioxide.

\($ S_2 - S_1 = 0.846 \ln (\frac{800}{400}) - 0.1889\ln (\frac{2000}{50}) $\)

\($ S_2 - S_1 = 0.846(0.69315) - 0.1889(3.6888) $\)

\($ S_2 - S_1 = 0.5864 - 0.6968 $\)

\($ S_2 - S_1 = -0.1104 \: \: kJ/kg.K$\)

Therefore, the entropy change of the carbon dioxide is -0.1104 kJ/kg.K

Answer:

a) What is the surface temperature, in °C, after 400 s?

   T (0,400 sec) = 800°C

b) Yes, the surface temperature is greater than the ignition temperature of oak (400°C) after 400 s

c) What is the temperature, in °C, 1 mm from the surface after 400 s?

   T (1 mm, 400 sec) = 798.35°C

Explanation:

oak initial Temperature = 25°C = 298 K

oak exposed to gas of temp = 800°C = 1073 K

h = 20 W/m².K

From the book, Oak properties are e=545kg/m³   k=0.19w/m.k   Cp=2385J/kg.k

Assume: Volume = 1 m³, and from energy balance the heat transfer is an unsteady state.

From energy balance: \(\frac{T - T_{\infty}}{T_i - T_{\infty}} = Exp (\frac{-hA}{evCp})t\)

Initial temperature wall = \(T_i\)

Surface temperature = T

Gas exposed temperature = \(T_{\infty}\)

The time-to-arm (TA) and time-to-burst (TB) settings on the B83 nuclear bomb are configured through the weapon's fuzing system.

The time-to-arm (TA) and time-to-burst (TB) settings on the B83 nuclear bomb are configured through the weapon's fuzing system.

The fuzing system is responsible for controlling the detonation sequence, and it allows the users to set the TA and TB values based on their desired operational requirements. The TA value ensures the weapon arms itself after a certain time period, while the TB value determines the time at which the weapon will detonate. These settings are crucial for the safe and effective use of the B83 nuclear bomb in various scenarios.

A fuze is a weapon subsystem that activates the warhead mechanism in the vicinity of the target and also maintains the warhead in a safe condition during all prior phases of the logistic and operational chain.

To know more about B83

https://brainly.com/question/31606414

#SPJ11

Given, the string S= bababbbaab Consider the table given below

The failure function π(k) is given by: The failure function is determined by comparing each character of the string to the longest possible prefix that is also a suffix of the string.

The longest prefix of the pattern that is also a suffix is called the border and its length is calculated at every position and stored in an array π.

If the pattern has no repeating substring (the trivial border of length 0), then π[0] = 0.

In order to compute the π array for the entire pattern, we begin with π[0] = 0, which is already defined.

Then we use the value of π[k] to compute π[k + 1].

Let j be the length of the border of S0,k, and S[j] be the next character.

Then we compare S[k + 1] with S[j + 1], and we repeat until we find the border of S0,k + 1.

To know more about array visit:

https://brainly.com/question/13261246

#SPJ11

yes it will

Explanation:

step: 1 of 16

The static thrust is defined as such a force which is developed and applied by the jet engine on the surrounding air or earth when the airplane is at rest condition.

Power is defined as the rate of doing work with respect to time. Power is a scalar quantity and having no direction. The unit of power is J/s  or watt in an hour(w) .

The expression to calculate the resultant power Ps  is,

PRETV  …… (1)

Here, Ps  is the required power, T R  is the required thrust and is the velocity of the airplane at a certain altitude.

The expression for the actual power for two engines is,

P, = 2(TV)  …… (2)

Here, т.  is the actual thrust and  is the velocity of the airplane for a given altitude.

step: 2 of 16

Write the expression for the thrust of an airplane.

TRE W CIC)  …… (3)

Here, T R  is the required thrust, W  is the weight of the airplane, с. is the lift polar coefficient of the airplane and Ср  is the drag polar coefficient of the plane.

Write the expression for the lift polar coefficient of the airplane.

W C 1 2P. Vis  …… (4)

Here, P  is the air density,  is the velocity of the airplane for a given altitude and S  is the wing area.

Write the expression for drag polar coefficient.

C, = CD,0 + C πε(AR)  …… (5)

Here, Сро  is the zero-lift drag coefficient,  is the Oswald’s efficiency factor and AR  is the aspect ratio.

It is clear from the power required curve that maximum velocity at the altitude at 5 km is

Hence, the required maximum velocity at the altitude of 5 km  is295 m/s.

You can learn more through link below:

https://brainly.com/question/15218114#SPJ4

Answer:

Explanation: Changing Lanes Tip 1: scan Explanation: When scanning you check all your mirrors while looking at the road in between, this keeps you aware of your surroundings. Tip 2: check blind spotExplanation: When checking your blind spot you quickly glance to which way you want to change lanes for no more than 2 seconds. Your peripheral vision will pick up any lights or movement. Tip 3: use signals Explanation: When changing lanes use you signal to alert others around you even if no ones around

Mass flow rate, m = ρ A V = (80/287) × π/4 × (0.1)² × 20 = 0.0267 kg/sInlet state,P₁ = 80 kPaT₁ = 20 °C Outlet state,P₂ = 800 kPaT₂ = 200 °CWork done,Win = 400 kW

ΔS = Cp ln (T₂/T₁) - R ln (P₂/P₁)= 1.005 ln (473/293) - 0.287 ln (800/80) = 0.8372 kJ/kg.K(b) Calculate the isentropic outlet temperatureT₂s = T₁ (P₂/P₁)^((γ - 1) / γ)= 293 (800/80)^((1.4 - 1) / 1.4) = 696.5 K(c) Calculate the actual outlet temperature.T₂ - T₁ = (Win/m) / Cp= (400 × 10³) / (0.0267 × 1.005) = 15047 KT₂ = 15047 + T₁ = 15047 + 293 = 15340 K(d) Calculate heat transfer.Q = m (Cp ΔT - ΔH)= 0.0267 × (1.005 × (15340 - 20) - 228.09)= -232.48 kW Therefore, the value of Q is -233 kW. MAIN ANS: Q = -233 kW (option c).

It is important to calculate heat transfer so that we can determine the energy required or generated by a system. We also determined the actual outlet temperature, entropy change, and isentropic outlet temperature.

Learn more about Mass flow rate here:

brainly.com/question/30763861

#SPJ11

The least value of extraterrestrial solar radiation is constant throughout the year. Therefore, the answer is option (c) Constant throughout the year. The extraterrestrial solar radiation is the amount of solar radiation received from the sun at the top of the Earth's atmosphere, the solar constant (Isc). The adjusted reading of the pyranometer is 82 W/m2.

The least value of extraterrestrial solar radiation is constant throughout the year. A pyranometer is an instrument used for measuring the solar irradiance (total energy flux from the Sun) that falls upon a planar surface. A pyranometer with a shading ring is used to measure diffuse radiation at a location with a latitude of 0°.If a pyranometer with a shading ring is used to measure diffuse radiation at a location with a latitude of 0° and it has a reading of 100 W/m2, the adjusted reading of this pyranometer will be as follows:

Let’s assume the correction factor of a pyranometer with a shading ring is 0.18. Therefore the adjusted reading of pyranometer is calculated as: Adjusted reading = (1 - 0.18) × reading= 0.82 × 100= 82 (W/m2).

Therefore, the adjusted reading of the pyranometer is 82 W/m2.

For Further Information on Pyranometer visit:

https://brainly.com/question/33201007

#SPJ11

Answer:

Time required = 287.2 secs  

Explanation:

Volume  of room = 25 * 10 * 4 = 1000 m^3

power consumed by pump = 15 kW

T1 ( initial temperature ) = 12°C

P1 ( Initial pressure ) = 1 bar

COPhp = 3

Calculate time taken to raise room Temp to 27°C

average heat supplied ( ∅ ) = COPhp * power consumed by pump

                                             = 3 * 15 = 45 kW

Time required can be calculated using the relation below

∅t = P*V*Cv ( T2 - T1 )   [ p = 1.2 kg/m^3 , Cv = 0.718 KJ/kg ( air properties ) ]

45 * 10^3 ( t )  = 1.2*1000* 718 ( 27 - 12 )

∴ solving for t

t = 287.2 secs  ≈ 4.79 mins

Answer:

I hope it helps :)

Explanation:

It is useful to measure Height and Arm Span in tennis players. Body fat can be measured using the skinfold method. If this is not available, monitoring body weight changes would give an indication of body fat changes, assuming no