Daily Archives: January 25, 2021

To what do you assign the peaks at m/z 64 and 34?

Portable mass spectrometers are now available for monitoring gaseous emissions from volcanoes.

Analyses after the eruption of the Turrialba Volcano in Costa Rica in January 2010 showed the presence of [M]+ ions (i.e. atomic ions and nonfragmented molecular ions) at m/z 64, 44, 40, 34, 32, 28 and 18. Mass spectra recorded before the eruption confirmed that the peak at m/z 64 was missing, and the peak at m/z 34 was substantially diminished.

(a) To what do you assign the peaks at m/z 64 and 34?

(b) Bearing in mind the composition of the Earth’s atmosphere, what molecular ion interferes with the detection of the volcanic emission observed at m/z 34?

(c) Volcanic gases mix with the surrounding air. Suggest what atmospheric gases give rise to the ions at m/z 40, 32 and 28.

(d) Sampling of the volcanic plume….

Why do natural diamonds not behave as semiconductors?

Almost all natural diamonds are impure and contain substitutional nitrogen. Clusters of N atoms are present in Type 1a diamonds (the most common defect structure), while Type 1b diamonds contain well-separated N atoms. (a) What is meant by ‘substitutional nitrogen’? (b) In what type of environment will an N atom reside in natural diamond? (c) Sketch a diagram to illustrate the band structure of diamond, assuming no defects. Explain why diamond is an insulator. (d) The donor-level associated with the nitrogen lies about 1.7 eV below the conduction band. How does this donor level arise? Why do natural diamonds not behave as semiconductors?

Explain briefly how the technique can be used to distinguish anatase and rutile.

(a) What analytical method is routinely used to screen polymorphs of a compound? Explain briefly how the technique can be used to distinguish anatase and rutile.

(b) What are the coordination environments of each Ti (IV) centre and O2- ion in anatase?

(c) Use the unit cell in Fig. 6.30 to confirm the stoichiometry of the anatase phase.

(d) Anatase preferentially crystallizes under ambient conditions and transforms to rutile at higher temperatures. At the structural level, how do you envisage the phase change taking place?

 

Give examples of other metal ions transported by metallothioneins.   

Sources of Cd include welding emissions, electronic components and NiCd batteries. EU and US legislations are now in place to reduce our exposure to Cd. Once absorbed into the body, Cd is targeted by metallothioneins, cysteine, the tripeptide glutathione and the protein albumin (Fig. 29.32) and is transported in the blood to the liver. (a) What features are highlighted in ball-and stick representation in Fig. 29.32?

Suggest how they originate in terms of the amino acid residues present in the protein. (b) Why are metallothioneins, cysteine, glutathione and albumin suited to binding Cd2+? (c) Give examples of other metal ions transported by metallothioneins.

incorporate most of the conceptstaught in ITD104.

Portfolio 2 Assignment: Online Shopping Application (10%, due Week 12, Sunday 24 January 11:59pm) Overview This is the first part of the second Portfolio-worth 10% of your final grade for ITD104.The Portfolio 2 Test is the second part of the Portfolio, and will be worth a further 15%.The Test will test you for the same skills required to complete this Assignment, under time pressure. Motivation The Internet has dramatically changed the way we conduct commerce. Online shopping is increasingly displacing traditional forms of retailing. Here you will develop an application that provides an online shopping experience, using data downloaded from the World Wide Web. The program will have a Graphical User Interface that allowsits user to choose which products they want to buy from different categories. Having done….

analyze associations among purchasesof these items for purposes of point-of-sale display, guidance to sales personnel in promoting cross-sales, andguidance for piloting an eventual time-of-purchase electronic recommender system to boost cross-sales.

The data are shown in Table 1 and the output in Table 2 is based on a subset of a dataset on cosmeticpurchases (Cosmetics.csv) at a large chain drugstore. The store wants to analyze associations among purchasesof these items for purposes of point-of-sale display, guidance to sales personnel in promoting cross-sales, andguidance for piloting an eventual time-of-purchase electronic recommender system to boost cross-sales.Consider first only the data shown in Table 1, given in binary matrix form.Table 1: Excerpt from data on cosmetics purchases in binary matrix formTasks1. Consider the results of the association rules analysis shown in Table 2.a. For the first row, explain the “confidence” output and how it is calculated.b. For the first row, explain the “support” output and how it is calculated.c. For the first….

What are the Characteristics of Negative Feedback?

Electrical Question: What are the Characteristics of Negative Feedback? Answer: Negative Feedback in a Control System has following Characteristics Reduction in the gain at the expense of better stability of the system Rejection of disturbance signals in the system Low Sensitivity to parameter variations Accuracy in tracking the steady state value What are the basic components of the feedback control system? Answer: Basic components of the feedback control system are process system (open loop system), feedback path element, error detector, and controller. Define Transfer Function? Answer: Transfer Function of a control system is defined as: i) Ratio of Laplace transform of Output to the Laplace transform of the Input with zero initial conditions

Discuss whether the work is being accomplished as planned and explain why.

The purpose of this assignment is to establish a baseline and record actual project data.

Review the “Project Execution” section of Chapter 3 in the textbook.

Part 1:

You will utilize the information and assignments from Topics 3 and 4 to formally baseline your project plans. The emphasis should be on schedule and cost.

Review Appendix A (pages 42-45) from the textbook. Follow the steps provided to guide your baseline process and the subsequent status of you plan.

Open the Microsoft Project “Global Treps Project Rev5” file created for the Topic 5 assignment and enter actual costs and durations associated with the project. Update Tasks 1-4 to 100% complete. Enter actual completion dates for Task 6. Make the “Actual Start” date the same as the “Current Start” date….

What is the expected dot product between a pair with 50,000 words each?

1.       Consider a text corpus with 106 documents, a lexicon of size 105, and 100 distinct words per document, which is represented as a bag of words with frequencies. (a) What is the amount of space required to store the entire data matrix without any optimization? (b) Suggest a sparse data format to store the matrix and compute the space required.

2.       In Exercise 1, let us represent the documents in 0-1 format depending on whether or not a word is present in the document. Compute the expected dot product between a pair of documents in each of which 100 words are included completely at random. What is the expected dot product between a pair with 50,000 words each? What does this tell you about the effect of….

Which problem discussed in this chapter would you use to determine the category of an incoming news article.

1.       Suppose that a news portal has a stream of incoming news and they asked you to organize the news into about ten reasonable categories of your choice. Which problem discussed in this chapter would you use to accomplish this goal?

2.       In Exercise 3, consider the case in which examples of ten pre-defined categories are available. Which problem discussed in this chapter would you use to determine the category of an incoming news article.

3.       Suppose that you have popularity data on the number of clicks (per hour) associated with each news article in Exercise 3. Which problem discussed in this chapter would you use to decide the article that is likely to be the most popular among a group of 100 incoming articles (not included in….