According to one government agency, bad housekeeping is estimated to cause what percentage

What is the definition of a tolerance on a dimension typically found on technical drawings?

Alinara [238K]

Tolerance is the acceptable amount of dimensional variation that still allows a part to perform as designed.

Any process will have variation and depending on the severity of the function some tolerance will be very small. For example the sheet metal thickness on portion of a space shuttle will have a much tighter tolerance than the thickness of a piece of lumber to build a house. Tighter tolerance of processes typically are related to more process control (e.g. money) thus designs should be fully vetted with process team before placing on a drawing.

7 0

3 years ago

A counter-flow double-piped heat exchange is to heat water from 20oC to 80oC at a rate of 1.2 kg/s. The heating is to be accompl

lawyer [7]

Answer:

110 m or 11,000 cm

Explanation:

let mass flow rate for cold and hot fluid = Mc and Mh respectively
let specific heat for cold and hot fluid = Cpc and Cph respectively
let heat capacity rate for cold and hot fluid = Cc and Ch respectively

Mc = 1.2 kg/s and Mh = 2 kg/s

Cpc = 4.18 kj/kg °c and Cph = 4.31 kj/kg °c

Using effectiveness-NUT method

First, we need to determine heat capacity rate for cold and hot fluid, and determine the dimensionless heat capacity rate

Cc = Mc × Cpc = 1.2 kg/s × 4.18 kj/kg °c = 5.016 kW/°c

Ch = Mh × Cph = 2 kg/s × 4.31 kj/kg °c = 8.62 kW/°c

From the result above cold fluid heat capacity rate is smaller

Dimensionless heat capacity rate, C = minimum capacity/maximum capacity

C= Cmin/Cmax

C = 5.016/8.62 = 0.582

.2 Second, we determine the maximum heat transfer rate, Qmax

Qmax = Cmin (Inlet Temp. of hot fluid - Inlet Temp. of cold fluid)

Qmax = (5.016 kW/°c)(160 - 20) °c

Qmax = (5.016 kW/°c)(140) °c = 702.24 kW

.3 Third, we determine the actual heat transfer rate, Q

Q = Cmin (outlet Temp. of cold fluid - inlet Temp. of cold fluid)

Q = (5.016 kW/°c)(80 - 20) °c

Qmax = (5.016 kW/°c)(60) °c = 303.66 kW

.4 Fourth, we determine Effectiveness of the heat exchanger, ε

ε = Q/Qmax

ε = 303.66 kW/702.24 kW

ε = 0.432

.5 Fifth, using appropriate effective relation for double pipe counter flow to determine NTU for the heat exchanger

NTU = $\\ \frac{1}{C-1} ln(\frac{ε-1}{εc -1} )$

NTU = $\frac{1}{0.582-1} ln(\frac{0.432 -1}{0.432 X 0.582 -1} )$

NTU = 0.661

.6 sixth, we determine Heat Exchanger surface area, As

From the question, the overall heat transfer coefficient U = 640 W/m²

As = $\frac{NTU C{min} }{U}$

As = $\frac{0.661 x 5016 W. °c }{640 W/m²}$

As = 5.18 m²

.7 Finally, we determine the length of the heat exchanger, L

L = $\frac{As}{\pi D}$

L = $\frac{5.18 m² }{\pi (0.015 m)}$

L= 109.91 m

L ≅ 110 m = 11,000 cm

3 0

3 years ago

Why is the face of the claw on a claw hammer usually a smooth curve? Why isn't it straight or some other shape?

GarryVolchara [31]

Answer:

The face of the claw on the claw hammer is usually a smooth curve so as to improve the ease with which nails are removed when removing nails because as the nail held between the V shaped split claw is being pulled out from the wood, it slides more and more towards cheek, reducing the distance of the nail from the cheek which is the fulcrum, thereby increasing the mechanical advantage because the location of the hand on the grip remains unchanged

Explanation:

7 0

3 years ago

What minimum radius of curvature may be designed for safe operation of vehicles at 70 mi/hr if the maximum rate of superelevatio

aleksandr82 [10.1K]

Tell me why i got this question got it right and now won’t remember but i’ll get back at you when i remember

5 0

3 years ago

Given that the company "Slate Rock and Gravel" has business locations in Granitetown and Bedrock, suppose that the company has b

kotegsom [21]

Answer:

Check the explanation

Explanation:

As Granitetown requires 5000 IP address and the starting IP address is 192.172.0.0 , we have to perform subnetting using number of hosts required

Number of IP address required by Granitetown=4000

Number of hosts bits =

2n -2= 5000

n=13 (approximately)

Number of hosts bits are 13 therefore subnet prefix =(32-13)=19

We have used 32 because IP address is of 32-bit

Subnet mask corresponding to /19 = 255.255.224.0

Starting IP address (given)= 192.172.0.0

Now to calculate last IP address of the subnet, OR operation will be performed between First IP address of the subnet and !Netmask

First IP address of subnet ( in binary) =

11000000.10101100.00000000.00000000

OR

00000000.00000000.00011111.11111111 (!Netmask)

11000000.10101100.000 11111.11111111 (result)

Converting result into decimal gives IP address 192.172.31.255 which will be the broadcast IP address of the subnet therefore

Last usable IP address = 192.172.31.254

Now, bedrock requires 2000 IP address

Therefore number of host bits are =

2n -2 =2000

n=10 (approximately)

Number of hosts bits required are 10

Therefore Netmask prefix = (32 -10) =22

Now, using the next subnet for bedrock therefore the first IP address of subnet will be 192.172.32.0

Now, similarly calculating last IP address of subnet

First IP address in binary =

11000000.10101100.00100000.00000000

OR

00000000.00000000.00000011.11111111 (!Netmask)

11000000.10101100.00100011.11111111 (result)

Now, result in decimal = 192.172.35.255

Therefore ,

Broadcast address of subnet =192.172.35.255

Last usable IP address =192.172.35.254

8 0

4 years ago