Answer:

**Answer:**

T = 858.25 s

**Explanation:**

Given data:

Reheat stage for a 100-mm-thick steel plate ( 7830 kg/m3, c 550 J/kg K, k 48 W/m K),

initial uniform temperature ( Ti ) = 200 c

Final temperature = 550 c

convection coefficient = 250 w/m^2 k

products combustion temp = 800 c

**calculate how long the plate should be left in the furnace ( to attain 550 c **)

first calculate/determine the Fourier series Number ( Fo )

= 0.4167 =

therefore Fo = 3.8264

Now determine **how long the plate should be left in the furnace**

Fo =

k = 48

p = 7830

L = 0.1

Input the values into the relation and make t subject of the formula

hence t = 858.25 s

The barrel of a bicycle tire pump becomes quite warm during use. Explain the mechanisms responsible for the temperature increase.

The sports car has a weight of 4500-lb and a center of gravity at G. If it starts from rest it causes the rear wheels to slip as it accelerates. Determine how long it takes for it to reach a speed of 10 ft/s. Also, what are the normal reactions at each of the four wheels on the road? The coefficients of static and kinetic friction at the road are us=0.5 and uk=0.3, respectively. Neglect the mass of the wheels.

A bathroom scale uses four internal strain gauges to measure the displacement of its diaphragm as a means for determining load. Four active gauges are used in a bridge circuit. The gauge factor is 2, and the gauge resistance is 120 Ω for each gauge. If an applied load to the diaphragm causes a tensile strain on R1 and R4 of 40 x 10-6, while gauges R2 and R3 experience a compressive strain of 40 x 10-6, estimate the bridge deflection voltage. The supply voltage is 5 V. a,b,c or d? a.400 x 10-6 V b.600x10-6V c.800x10-6V d.1000 x 10-6 V

A cylindrical specimen of a hypothetical metal alloy is stressed in compression. If its original and final diameters are 20.000 and 20.025 mm, respectively, and its final length is 74.96 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 105 GPa and 39.7 GPa, respectively.

As a means of preventing ice formation on the wings of a small, private aircraft, it is proposed that electric resistance heating elements be installed within the wings. To determine representative power requirements, consider nominal flight conditions for which the plane moves at 100 m/s in air that is at a temperature of -23 degree C. If the characteristic length of the airfoil is L = 2 m and wind tunnel measurements indicate an average friction coefficient of of C_f = 0.0025 for the nominal conditions, what is the average heat flux needed to maintain a surface temperature of T_s = 5 degree C?

The sports car has a weight of 4500-lb and a center of gravity at G. If it starts from rest it causes the rear wheels to slip as it accelerates. Determine how long it takes for it to reach a speed of 10 ft/s. Also, what are the normal reactions at each of the four wheels on the road? The coefficients of static and kinetic friction at the road are us=0.5 and uk=0.3, respectively. Neglect the mass of the wheels.

A bathroom scale uses four internal strain gauges to measure the displacement of its diaphragm as a means for determining load. Four active gauges are used in a bridge circuit. The gauge factor is 2, and the gauge resistance is 120 Ω for each gauge. If an applied load to the diaphragm causes a tensile strain on R1 and R4 of 40 x 10-6, while gauges R2 and R3 experience a compressive strain of 40 x 10-6, estimate the bridge deflection voltage. The supply voltage is 5 V. a,b,c or d? a.400 x 10-6 V b.600x10-6V c.800x10-6V d.1000 x 10-6 V

A cylindrical specimen of a hypothetical metal alloy is stressed in compression. If its original and final diameters are 20.000 and 20.025 mm, respectively, and its final length is 74.96 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 105 GPa and 39.7 GPa, respectively.

As a means of preventing ice formation on the wings of a small, private aircraft, it is proposed that electric resistance heating elements be installed within the wings. To determine representative power requirements, consider nominal flight conditions for which the plane moves at 100 m/s in air that is at a temperature of -23 degree C. If the characteristic length of the airfoil is L = 2 m and wind tunnel measurements indicate an average friction coefficient of of C_f = 0.0025 for the nominal conditions, what is the average heat flux needed to maintain a surface temperature of T_s = 5 degree C?

Answer:

The answer is

Explanation:

The compressibility factor

**Answer:**

the relative compaction is **105.88 %**

**Explanation:**

Given;

dry unit weight of field compaction, = 18 kN/m³

maximum dry unit weight measured, = 17 kN/m³

Relative compaction (RC) of the site is given as the ratio of dry unit weight of field compaction and maximum dry unit weight measured

Relative compaction (RC) = dry unit weight of field compaction / maximum dry unit weight measured

substitute the given values;

RC (%) = 105.88 %

Therefore, the relative compaction is **105.88 %**

Answer:

A. 450 btu/h

Explanation:

We solve this problem by using this formula:

Q = U x TD x area

U = U value of used material

TD = Temperature difference = 60°

Q = heat loss

Area = 3x5 = 15

We first find U

R = 1/u

2 = 1/U

U = 1/2 = 0.5

Then when we put these values into the formula above, we would have:

Q = 0.5 x 15 x 60

Q = 450Btu/h

Therefore 450btu/h is the answer

**Answer:**

A) 0.0614 inches

b) The standard steel paper clip should float on water

**Explanation:**

The maximum diameter that the rod can have before it will sink

we can calculate this using this formula :

D = ----- 1

∝ = value of surface tension of water at 60⁰f = 5.03×10^−3 lb/ft

y = 490 Ib/ft^3

input the given values into equation 1 above

D =

= 5.11 * 10^-3 ft convert to inches

= 5.11 *10^-3 ( 12 in/ 1 ft ) = 0.0614 inches

B) The diameter of a standard paper Cliphas = 0.036 inches

and the diameter of the rod = 0.0614. Hence the standard steel paper clip should float on water

b) Thermal barrier coating. Cement, aluminum, engineering ceramic, super alloy, steel and glass

**Answer:**

Answer explained below

**Explanation:**

3.] a] A turbine blade is the individual component which makes up the turbine section of a gas turbine. The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor.

The turbine blades are often the limiting component of gas turbines. To survive in this difficult environment, turbine blades often use exotic materials like superalloys and many different methods of cooling, such as internal air channels, boundary layer cooling, and thermal barrier coatings. The blade fatigue failure is one of the major source of outages in any steam turbines and gas turbines which is due to high dynamic stresses caused by blade vibration and resonance within the operating range of machinery.

To protect blades from these high dynamic stresses, friction dampers are used.

b] Thermal barrier coatings (TBC) are highly advanced materials systems usually applied to metallic surfaces, such as on gas turbine or aero-engine parts, operating at elevated temperatures, as a form ofexhaust heat management.

These 100μm to 2mm coatings serve to insulate components from large and prolonged heat loads by utilizing thermally insulating materials which can sustain an appreciable temperature difference between the load-bearing alloys and the coating surface.

In doing so, these coatings can allow for higher operating temperatures while limiting the thermal exposure of structural components, extending part life by reducing oxidation and thermal fatigue.

In conjunction with active film cooling, TBCs permit working fluid temperatures higher than the melting point of the metal airfoil in some turbine applications.

Due to increasing demand for higher engine operation (efficiency increases at higher temperatures), better durability/lifetime, and thinner coatings to reduce parasitic weight for rotating/moving components, there is great motivation to develop new and advanced TBCs.

**Answer:**

The horizontal conductivity is 41.9 m/d.

The vertical conductivity is 37.2 m/d.

**Explanation:**

**Given that,**

Thickness of A = 8.0 m

Conductivity = 25.0 m/d

Thickness of B = 2.0 m

Conductivity = 142 m/d

Thickness of C = 34 m

Conductivity = 40 m/d

**We need to calculate the horizontal conductivity**

**Using formula of horizontal conductivity**

Put the value into the formula

**We need to calculate the vertical conductivity**

**Using formula of vertical conductivity**

Put the value into the formula

**Hence, The horizontal conductivity is 41.9 m/d.**

**The vertical conductivity is 37.2 m/d.**