Question 610 pts

A BOD test is run using 10 mL of treated wastewater. Chemicals to inhibit nitrification were added. The initial dissolved oxygen (DO) in the bottle is 9.5 mg/L and after 5 days, the DO is 5.0 mg/L. For the bottles that were allowed to run for 20 days, the DO is 4.0 mg/L. A similar test was done where nitrification was not inhibited. The initial DO was the same and the DO after 20 days was 3.0 mg/L. What is the BOD₅, ultimate BOD (BOD_u)  and the nitrogenous NBOD. BOD bottle volume is 300 mL.

B O D ( m g L ) = D 1 − D 2 ( m g L ) P

D1 = DO in bottle immediately after preparation

D2 = DO in sample after t days

P = fraction of sample volume to total volume

Group of answer choices

135, 165 and 195 mg/L

13.5, 16.5 and 19.5 mg/L

10.8, 43.8 and 33 mg/L

1350, 438 and 1080 mg/L

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Question 710 pts

You carried out solids analysis of a sample collected from an industrial site. The data is as follows:

Weight of crucible = 42.4523 g

Volume of sample = 25 mL

The weight of the crucible and dry solids after drying at 105°C = 42.4986 g

Weight of crucible and residue after burning off at 550°C = 42.4863 g

The total solids, volatile solids and fixed solids are

Group of answer choices

926, 246 and 680 mg/L, respectively

926, 680 and 246 mg/L, respectively

105.2, 56.0 and 49.2 mg/L, respectively

1052, 560 and 492 mg/L, respectively

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Question 85 pts

A wastewater sample was collected from a treatment plant and sent for quality analysis. The BOD test was carried out over 20 days. No chemicals to inhibit nitrification were added. The BOD value in this case is a measure of the concentration of ___________ in the wastewater

Group of answer choices

almost all carbonaceous and nitrogenous compounds

all organic and inorganic compounds present in the wastewater

particulate organic carbonaceous and nitrogenous compounds

almost all dissolved nitrogenous organic compounds

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Question 95 pts

During the_____________ phase, the number of microorganisms (in the BOD bottle) is more than during the _______________phase, but the rate of production is lower

Group of answer choices

declining growth, log growth

log growth, declining growth

declining growth, endogenous respiration

log growth, endogenous respiration

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Question 105 pts

Aerobic autotrophic bacteria

Group of answer choices

Get their energy from oxidation of inorganic compounds, e.g. NH₄, carbon from CO₂ and O₂ from air (or mixers)

Get their energy from oxidation of inorganic compounds, e.g. NH_4, carbon from CO₂ and do not need O₂

Get their energy from the sun (i.e. photosynthesis reactions) and carbon from CO₂

Get their en

Q1: Analysis of forces and moments were done for a simply supported beam having span 10 m
carrying a uniformly distributed load of ‘w’ kN/m over a length of 5 m from the left end support
and point loads ‘2w’ kN, ‘3w’ kN and ‘1.5w’ kN at distances of 6 m, 7 m and 8 m respectively from
the left end support. It was observed that the maximum bending moment acting on the beam is
equal to 192 kNm. Suggest a suitable value for ‘w’ based on this loading condition. How it will
change the reactions at the supports? What happens to the shear force and bending moment
values at the supports and at the points where loads acting? By plotting the bending moment and
shear force diagram for the beam, briefly conclude the relationship between the values for shear
force and bending moment.

An axial pull of 45 kN is applied on the three bars of varying cross section and connected to
each other as shown in figure. Two outer steel bars are of same length and diameter, but the
middle bar made up of brass having cross sectional dimensions 20 mm x 20 mm. The length of the
middle bar used was 4 times more than that of the two outer bars and stress in the two outer
portion were found to be 175 N/ mm2 causing a total elongation of 13.25 mm. Consider the values
for modulus of elasticity of steel equal to 205 x 105 N/cm2 and the modulus of elasticity for brass
equal to 88 x 105 N/cm2. Recommend a suitable value for the diameter of the two outer bars and
length of all three sections based on the given data.
If all three bars are made up of steel having modulus of elasticity 98 kN/mm2 and shear modulus
410 tonnes/cm2, what will be the values for the lateral dimensions of all three bars? Verify the
relationship between lateral strain and longitudinal strain based on the findings.

Q3: When a mild steel rod was tested under tension, it was observed that a load of 8 kN causes an
extension of 0.024 cm in the rod. The maximum load carried by the steel rod was observed to be
20 kN and the load beyond which stress is not proportional to strain was noted as 10 kN. When the
specimen breaks, the elongation in the rod measured was 5.25 cm and the diameter at the fracture
observed was 0.455 cm. What will be the length and diameter of the steel rod if the total
elongation of the steel rod was found to be 25% and the area of contraction at fracture estimated
was 12%? Based on the test results, determine the values for the stress corresponding to limit of
proportionality, modulus of elasticity of the material and the ultimate stress developed due to
tension.

Comparative study was done on two girders one simply supported with eccentric loading and
the other cantilevered with uniformly distributed load. Data’s are tabulated as follows:
Type of beam Simply supported Cantilever
Span 7.5 m 3.5 m
Loading point load of 45 kN at
distance of ‘a’ from left
support
uniformly distributed load ‘w’ N/mm
over the entire span
Slope of the beam at left
end support ??
0.0075 radians Not given

Position of maximum
deflection
4.7 m from the right end
support
Not given
Maximum deflection Ymax 17.5 mm
Determine the value of ‘a’ in meters for the simply supported beam. Also find the slope at right
hand support ?? and the magnitude of maximum deflection (Ymax) for simply supported beam.
What will be the value for ‘w’ and the maximum slope for cantilever beam? Take EI = constant.
Based on the conclusions, explain how the deflection of a beam can be minimized by varying the
magnitude and the position of the load? (8 marks

Q1: A cantilever beam having span ‘L’ m was subjected to a uniformly distributed load of
magnitude 8 kN/m for a distance of ‘0.6 L’ from the free end and two concentrated loads one of
magnitude 15 kN at a distance ‘0.25 L’ m from the free end while the other of magnitude ‘22’ kN at
a distance ‘0.6 L’ m from the free end respectively. It was observed that the maximum bending
moment acting on the beam is equal to (-369 kNm). Suggest a suitable span for the beam based on
the loading condition. How it will change the reaction at the fixed support? What happens to the
shear force and bending moment values at the fixed support, free end and at the center of the
beam? By plotting bending moment and shear force diagram for the beam briefly conclude the
relationship between the values for shear force and bending moment.

Research the following notable engineering failures. Discuss how analysis was used or could have been used to investigate the failure.   

Highway I-880, Loma Prieta, California earthquake, 198

Please determine if the following statement is true or false, and explains why.

1. Effective stress is defined as total stress minus pore pressure.

2. For a given consolidation stress, a normally consolidated clay will be stronger than an overconsolidated clay.

3. The sequent depth, ys of a hydraulic jump in a rectangular channel is related to the initial yi, the discharge per unit length, q, gravity acceleration, g and density r. Express the ratio ys/yi in term of non-dimensional group and compare with the equation developed from momentum principles as shown below:

                                                                                ?! _#              

Write 5+ pages in one of the following topics :- ( MAKE SURE THE HANDWRITING IS READABLE, * I prefer to be made in M.S word )

1- Contaminant transport in groundwater

2- Modeling of contaminant transport in groundwater

Parameter Steel .

Modulus of Elasticity 30,000,000 psi

Proportional/Elastic Limit 34,000 psi

Allowable Bending Stress 24,000 psi

Allowable Axial (C or T) Stress 24,000 psi

Allowable Shear Stress 16,500 ps

You have a 25-foot long, simply supported W12-50 steel beam. It is supporting a single 10,000# point load at its midpoint. Including the weight of the beam, answer the questions below:

A. What is the maximum bending moment (foot-#) and resulting maximum bending stress (psi)? Is this allowable?

B. What is the maximum vertical shear (#) and resulting average shear stress (psi)? Is this allowable?

C. What is the maximum deflection (inches)? Is this permissible if the allowable deflection is (1:360)?

describe the most difficult-to-deal waste that is being produced in your household and suggest how to treat it