a. Interstitial atoms belong to line defects, yes or no?

b. What is the influence of crystallinity increase on polymer modulus?

c. Why are polymers lighter than metals and ceramics? Two reasons.

d. How can glass fiber be made (name 2 methods/procedures)? 23 24 25 26

e. What are the three main types of materials discussed in EGR218?(Ceramics , polymers & metals?)

f. What are the three limitations of ferrous alloys, generally?

g. Why poly crystals are stronger than single crystals?

h. Can polymers be purely crystalline? Yes/No

i. What are the three functions of screen pack in polymer extruding?

In: Civil Engineering

A concrete for a weave breaker is to be designed at a w/c
ratio of 0.45. A maximum size of aggregate of 25 mm was used hence
a water content of 200 kg/m3 (with 2% air) was required to achieve
satisfactory workability. Both the coarse and fine aggregate
conform to the grading requirements of ASTM C33. The fine aggregate
having a fineness modulus of 2.4, and an absorption of 2%, a BSG
(SSD) of 2.6, whereas the coarse aggregate have a bulk density of
1500 kg/m3; an absorption of 3% and a BSG (SSD) of 2.50. The
moisture content for both aggregate is 2%. Compute mixture
proportions (in kg/m^3) before and after moisture corrections
following ACI procedure.

In: Civil Engineering

A falling head permeability test was performed on a re-moulded silty clay soil sample 150 mm in diameter and 250 mm in length. The diameter of the standpipe was 12.7 mm. At the start of the test, the height of the water in the standpipe measured 2,236 mm above the constant water level where the soil sample was immersed in. After 7 hours and 45 minutes, the height of the water in the standpipe was measured at 1971 mm. Determine: (i) the coefficient of permeability of the soil (in m/sec), and (ii) the estimated height of the water in the standpipe after a further 12 hours of running this test. (iii) the total time (from the start of the test in days, hours, minutes and seconds) it will take for the water level in the standpipe to reach a height of 600 mm.

In: Civil Engineering

Project management process involves many phases. Construction is one of the phases. Which of the following aspects of the construction phase do you consider as most important as well as most challenging/demanding? Why do you think so?

Third party coordination

Quality Management

Safety management?

Please select only one option and justify your response.

In: Civil Engineering

11-1 A particular tilted aerial photograph exposed with a 152-mm-focal length camera has a tilt angle 2°45’ and a swing angle of 140°00’. On this photograph, what are the auxiliary x' and y photocoordinates for points a and b, whose photocoordinates measured with respect to the fiducial axes are xa = 69.27 mm, ya = -41.80 mm, xb = -54.72 mm, and yb = 106.38 mm?

11-3 Calculate photographic scale for image points a and b of Prob. 11-1 if flying height above datum was 7.200 ft and if elevations of points A and B were 865 ft and 1,232 ft above datum, respectively.

11-8 Compute the tilt displacement of the two points in Prob. 11-1

In: Civil Engineering

A Seven-sided closed field traverse has the following angles and distances in meters which were measured using a Total station:

*AB* = 51.7660;

*BC* = 76.9470;

*CD* = 37.0700;

The adjusted angles are as follows:

*A* = 128˚27’02”;

*B* = 101˚41’49”;

*C* = 102˚22’05”;

*D* = 143˚12’43”;

*E* = 161˚08’23”;

*F* = 131˚57’22”;

*G* = 131˚10’35”;

*DE* = 29.2019;

*EF* = 28.7758;

*FG =* 36.7056;

*GA* = 41.9555;

azimuth AB =251˚00’00''

*question*

- Compute the coordinates of the traverse stations using
coordinates of station
*A*as 1,000.000 N, 1,000.000 E. - Compute the area enclosed by the traverse using the co-ordinate method.
- It was decided to divide the traverse into two parts AGFED and DCBA, find the area of each part and the length and direction of AD.

In: Civil Engineering

A 16-ft long pin-pin column has to support a dead load of 100 kips and a live load of 280 kips. Using column selection tables from the Steel Manual select columns for the given shapes. All selections should be structurally safe and least weight.

50-ksi W-section (W10, 12, 14 only)

35-ksi pipe (standard, x-strong, xx-strong)

46-ksi rectangular HSS

46-ksi square HSS

42-ksi round HSS

In: Civil Engineering

square footing 4×4 m carrying a load of 400 KN and the moment of 200 KN.m compute the maximum and minimum bearing pressure

In: Civil Engineering

**Responses may be 2-3 short sentences, diagrams, and/or
equations as described in the question.**

What is a principal plane and why is it important to determine its orientation?

In: Civil Engineering

**Describe the movement of powder particles during compaction in powder-metallurgy process. What features are responsible for the fact that powder does not flow and transmit pressure like a liquid?**

In: Civil Engineering

What are the roles, responsibilities, and risks (including risks for payments, ect.) for an owner on a construction project?

In: Civil Engineering

Edit question write a career plan for a full stack web developer

In: Civil Engineering

Explain why metals are electrically conducting and ceramics are good insulators.

In: Civil Engineering

The lattice parameters of a BCC metal is 3.1468 Å. Calculate:

(a) Interplanar spacing and the size of Burgers vector for slip system (111)[1 1̅ 0].

(b) Interplanar spacing and the size of Burgers vector for slip system (101)[111̅].

(c) What is the ratio between the shear stress required for slip for the two systems ( ?(111)[1 1̅ 0] / ?(101)[111̅] )? Assume that k=2.

In: Civil Engineering

You are a failure analysis engineer who must certify the integrity of an engineering component. Your component manufacturer has informed you that the plane strain fracture toughness of the component is measured to be as high as 140 ???√? and certifies that the surface cracks observed in the components are not bigger than 0.01 mm. During service, this component is to be continuously cycled at 3000 revolutions per minute between compressive and tensile stresses of 350 MPa. Assume that ? = 1.12 for all possible surface cracks. Materials constants are ? = 3.4 and ? = 2 × 10^−15 .

(a) You have access to three non-destructive testing techniques as shown in the table below. By calculating the critical crack length required to cause fracture, determine if any of the three techniques can be used to detect the crack before the fracture of the component.

Technique | Smallest detectable crack (mm) |

X-ray radiography | 0.50 |

γ-ray radiography | 0.2 |

Ultrasonic inspection | 0.13 |

(b) If you are to remove the component as soon as the crack length reaches 55% of the critical crack length to cause fracture, determine how many useful hours of the life of this component remains.

In: Civil Engineering