Examination Information and Rubric Guide

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Questions and Answers

What is the overall purpose of the methane emissions studies discussed in the text?

The overall purpose of the methane emissions studies discussed in the text is to optimize feed intake in cattle to reduce methane emissions.

What type of facility are the cattle housed in?

The cattle are housed in naturally ventilated buildings.

From the graph, what is the value of the amplitude (A) of the periodic function?

13.5 g/hr
7 hours
24 hours
2.5 g/hr (correct)

The formula for the model of methane emissions is M = ______ * sin[(t − S)/24] + 13.5

2.5 Signup and view all the answers

What are the units of the methane emission model M?

g/hr Signup and view all the answers

The graph in Question 1 represents the mean hourly methane emissions. Which of these is a possible limitation of this model?

All of the above. (D) Signup and view all the answers

Identify two general approaches for developing a suitable model for the data in Figure 2. Choose the two most suitable approaches from the following:

Functional form: Exponential, Power function (A), Develop a model: Use several points to determine constants, Use log-log and log-lin plots (C) Signup and view all the answers

In Question 2, what is the purpose of the DNN plume test?

The DNN plume test is designed to identify plumes of methane in the atmosphere. Signup and view all the answers

What is the prevalence (total number of plumes) in this sample?

5,660 (B) Signup and view all the answers

What is the probability of finding a plume if the DNN test predicts no plume?

9.4% Signup and view all the answers

Which of these is a disadvantage of the DNN plume test?

It misses more plumes than the SWIR bands plume test. (B) Signup and view all the answers

What is the annual rate of methane production by the landfill site in Mexico City after 11 years?

2 x 10⁷ m³/yr Signup and view all the answers

What quantity does the area under the curve represent in the context of methane production in a landfill?

The total methane produced over a given time period. Signup and view all the answers

Which of these methods can be used to estimate the accuracy of the trapezoid rule calculation?

All of the above (D) Signup and view all the answers

What is the methane production rate at the landfill site in Mexico City after 20 years?

0.8 x 10⁷ m³/yr Signup and view all the answers

What is the initial estimate (t0) used for the methane production model in Question 4?

5 years (B) Signup and view all the answers

What is the value of the methane production M(t) after 5 years?

1.372 x 10⁹ m³/yr Signup and view all the answers

What is the derivative of the methane production model M(t)?

M'(t) = (617.4 x 10³ – 68.6 x 10³t) t³.⁵e⁻⁰.⁵t Signup and view all the answers

What is the value of t1 after one iteration of Newton's method?

5.68 years Signup and view all the answers

What is the code snippet in the program for implementing Newton's method?

val = val - f(val)/df(val) Signup and view all the answers

What is the purpose of the condition 'abs(f(val)) > 0.0001' in the program?

The condition 'abs(f(val)) > 0.0001' controls the iterations in the program. It ensures that the loop continues until the absolute value of the function f(val) becomes less than 0.0001, which is a criterion for stopping the iterations. Signup and view all the answers

What is the surge function that models methane production in an Australian landfill?

MAustralia(t) = 894.4 x 10³t⁴.⁸e⁻⁰.⁸t Signup and view all the answers

Which of these statements about the graphs of the two methane production models (Mexico and Australia) is true?

The Australian model reaches its maximum value at a higher time than the Mexican model. (C) Signup and view all the answers

What is the time it takes for the Australian landfill methane model to reach its maximum value?

6 years Signup and view all the answers

What is the time it takes for the Mexican landfill methane model to reach its maximum value?

9 years Signup and view all the answers

What is the general form of the rate of change equation for the methane production models discussed in the text?

M'(t) = r(1 − M / K) * M Signup and view all the answers

What value of K for the CD + WR model is provided in the text's context?

K = 83 mL/g Signup and view all the answers

Explain the physical significance of K in the context of methane production.

K represents the carrying capacity of the reactor. It signifies the total amount of methane that can be produced from the reactor given the input materials, after all reactions are complete. This represents the maximum value that the cumulative methane output can reach for a given amount of input. Signup and view all the answers

What is the value of the methane production (M) after one day using Euler's method for the CD + WR + CS model, using the parameters provided?

2.20 mL/g Signup and view all the answers

In the context of methane production models, why are they called models?

Methane production models are simplified representations of complex processes. They make assumptions and idealizations to capture and predict the behavior of the methane production system within the reactor. This simplification is done to make the system more manageable for analysis and prediction. Signup and view all the answers

Explain why the models can be useful for comparing methane production across different reactors, even if they are idealized.

Despite their idealities, the models can provide insights into the general trend of methane production under different conditions. These models allow for a comparative analysis across different scenarios, like comparing methane production in a reactor with CD + WR input to one with CD + WR + CS input. This allows researchers to evaluate the effects of different inputs and conditions on the overall methane production process while acknowledging the inherent limitations of the models. Signup and view all the answers

What is the primary source of methane produced by cattle?

Feed fermentation (D) Signup and view all the answers

Methane is a less potent greenhouse gas than carbon dioxide.

False (B) Signup and view all the answers

Which of these methods can be used to identify sources of methane emissions from space?

All of the above (D) Signup and view all the answers

What is the process by which organic matter is broken down in the absence of oxygen to produce methane?

Anaerobic digestion Signup and view all the answers

Flashcards

Methane (CH4)

A potent greenhouse gas produced from organic matter decomposition.

Anthropogenic Sources

Human activities contributing to methane emissions.