In: Mechanical Engineering

A generous amount of gel is applied to the surface of the window of an ultrasound probe prior to its use. The window is made of a polycarbonate material of density ρ = 1200 kg/m3, thermal conductivity k = 0.2 W/m · K, and specific heat cp = 1200 J/kg · K. The probe is initially at a temperature of Ti = 20°C. To ensure that the gel remains adhered to the probe until the probe is brought into contact with the patient's skin, its temperature-dependent viscosity must not fall below a critical value. This corresponds to a requirement that the maximum gel temperature remain below 12°C prior to making contact with the patient. Determine the required initial gel temperature. The thermal conductivity, density, and specific heat of the gel may be assumed to be those of liquid water.

The correct method is to use the Surface Convection of Transient Conduction (Case 3 in Theodore Bergman, Adrienne Lavine 8th edition - Page 289, Equation 5.66)

A generous university benefactor has agreed to donate a large
amount of money for student scholarships. The money can be provided
in one lump sum of $12 million in Year 0 (the current year), or in
parts, in which $7 million can be provided at the end of Year 1,
and another $7 million can be provided at the end of Year 2.
Describe your answer for each item below in complete sentences,
whenever it is necessary. Show all of...

A rear window defroster consists of a long, flat wire bonded to
the inside surface of the window. When current passes through the
wire, it heats up and melts ice and snow on the window. For one
window the wire has a total length of 12.0 m, a width of 1.8 mm,
and a thickness of 0.12 mm. The wire is connected to the car's 12.0
V battery and draws 12.0 A. What is the resistivity of the wire
material?

The inner and outer surface temperatures of a glass window 5 mm
thick are 15 and 5°C. The thermal resist- ance of the glass window
due to conduction is Rt,cond = 1.19 × 10−3 K/W.
What is the rate of heat loss through a 1 m × 3 m window? What is
the thermal conductivity of the glass?

Write a SELECT statement that uses an aggregate window function
to get the total amount of each order. Return these columns:
The order_id column from the Order_Items table
The total amount for each order item in the Order_Items table
(Hint: You can calculate the total amount by subtracting the
discount amount from the item price and then multiplying it by the
quantity)
The total amount for each order Sort the result set in ascending
sequence by the order_id column.
Part...

For the cultivation of a cereal, an amount of fertilizer x is
applied in Kgs, per unit area and the quantity y of tons of
production is obtained. The following data is available:
x 99 100 101 102 103 104 105 106
y 2.1 2.8 7.2. 9.9 9.3 13.6 14.7 17.1
Do the test: H_0: β1 = 0 VS H_1: β1 ≠ 0 . Use α =
0.005.
Make a confidence interval (α = 0.005) for β1.
What would be a...

Write a paragraph commenting on the amount of pressure applied
by the cytoplasm and cell membrane against the cell wall under,
Turgid state and a state of plasmolysis in an Elodea cell(s) ( the
state of plasmolysis is caused by introduction of salt water(

A 38.0-kg crate is being pushed along a horizontal surface. The
applied force is 94.0 N directed at an angle of 18.0° below the
horizontal and the coefficient of friction is .21.
a) Draw a free body diagram for the crate.
b) Write expressions for the x and y components of
the applied force (no numbers).
c) Sum forces in the x and y direction (no
numbers).
d) Solve: What is the acceleration of the
crate?

Cretin Enterprises uses a predetermined overhead rate of $7 .50 per direct labour hour. This predetermined rate was based on 16,000 estimated direct labour-hours and $120,000 of estimated total manufacturing overhead. The company incurred actual total manufacturing overhead costs of $114,750 and 15,500 total direct labour-hours during the period. There were no beginning inventories, and all goods produced in the period were shipped out to customers before period end.
Required:
1. Determine the amount of under applied or over...

Applied Nanotech is thinking about introducing a new surface
cleaning machine. The marketing department has come up with the
estimate that Applied Nanotech can sell 15 units per year at
$311,000 net cash flow per unit for the next four years. The
engineering department has come up with the estimate that
developing the machine will take a $14.8 million initial
investment. The finance department has estimated that a discount
rate of 10 percent should be used. a. What is the...

Applied Nanotech is thinking about introducing a new surface
cleaning machine. The marketing department has come up with the
estimate that the company can sell 15 units per year at $308,000
net cash flow per unit for the next five years. The engineering
department has come up with the estimate that developing the
machine will take a $15.2 million initial investment. The finance
department has estimated that a discount rate of 16 percent should
be used. a. What is the...

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