Introduction

Thesis >> Introduction

The following table features the title (Column A) and the sub-headings of the Introduction chapter of a thesis from Mechanical Engineering (Column B). The key terms in the title are coded in different colors. Use the colour palette provided to identify their corresponding sub-headings in Column B (Table of Contents for the Introduction chapter).

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Column A: Title

Column B: Sub-headings of the Introduction chapter

Combustion, Thermal and Emission Characteristics of Gas-fired Inverse Diffusion Flames Burning mixed LPG–Hydrogen Fuel

Chapter 1. Introduction

1.1 Inverse Diffusion Flame
1.2 Liquefied Petroleum Gas (LPG) and Hydrogen (H₂) fuels.
1.3 Scope and Objectives of the Present Study
1.4 Thesis Organisation

Adapted from: J. Miao, “Combustion, Thermal and Emission Characteristics of Gas-fired Inverse Diffusion Flames Burning mixed LPG-Hydrogen Fuel”, Ph. D dissertation, Dept. of Mech. Eng., HKPOLYU, Hong Kong, 2015. [Online]. Available: HK PolyU Electronic Theses.

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The purpose of an Introduction refers to its communicative function, which is to communicate specific information about the thesis to the reader.

The six communicative purposes of an Introduction
In general, an Introduction has six communicative purposes which together help the reader to understand the background to the study and the motivation for the research.

To identify the research topic and establish its significance.
To review and evaluate previous research to identify aspects of the topic that need to be investigated.
To identify the specific research gap the study aims to address.
To indicate how the study addresses the research gap being investigated.
To establish the contribution the research makes to the broader field of study it relates to.
To signal the organisation of information in the thesis.

Activity 1

Activity 1

The following table presents extracts from the Introduction chapter of a thesis from Mechanical Engineering (Column A). They are not in the same order as in the thesis.

Column B of the table lists options for the six communicative purposes. Read each extract and select one purpose from the six options provided. Each extract only has one correct option.

Column A ( Extracts from Theses)	Column B ( Communicative Purposes)	Column B ( Communicative Purposes)
Research on pollutant emissions of hydrogen-enriched flame has obtained contradicting results. Some researchers found that hydrogen addition reduced CO/CO2 emissions from hydrocarbon flames (Burbano et al., 2008; Schefer et al., 2002) and internal combustion engines (Ji and Wang, 2009; Zuohua Huang et al., 2006), while other researchers found slight increment in CO/CO2 emissions (Lder et al., 1996; Tseng, 2002). Therefore, the effects of hydrogen addition to LPG appear to be far more complicated than expected.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis. From the review of the research on pollutant emissions of hydrogen-enriched flame, this study will examine the effects of LPG-Hydrogen fuel.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.
To date, most of the investigations related to IDF focus on flame appearance, soot loading and thermal performance. There is limited research concerning the effects on these characteristics by using a specially improved fuels mixture.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.
Flame is a special kind of combustion reaction, which can propagate subsonically through space (Pritchard et al., 1977). Flame can also be regarded as a kind of fluid flow with simultaneous chemical reactions taking place. Generally, flame can be classified into […]. In the present study, a particular flame type: inverse diffusion flame (IDF) is studied […].IDF is believed to have significant potential in domestic and industrial applications.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.
Considering the inevitable CO/CO2 emissions in LPG and difficulties in using pure hydrogen in large scale, it is expected that mixture of LPG and H2 may balance the properties of LPG and H2 to become a gaseous fuel with high reliability, low pollutant emissions and good thermal performance. The combination […] seems to be a feasible solution to overcoming the drawbacks and to adopting the advantages of both fuels.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.
The overview and the objectives of this study are presented in Chapter 1. Relevant previous research is reviewed and discussed in Chapter 2. Chapter 3 describes the equipment used and operational processes of experiments. Detailed experimental results are presented and discussed from Chapter 4 to Chapter 8. The main conclusions drawn from this study and recommendations for further research can be found in Chapter 9.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis. Words that highlight organisation of information are in bold.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.
LPG and H2 mixture, as discussed in previous section, is a kind of fuel mixture with potential advantages as well as uncertainties. The use of LPG/H2 mixture in IDF would be a new goal in scientific research on combustion and flame.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.	To identify the research topic and establish its significance. To review and evaluate previous research to identify aspects of the topic that need to be investigated. To identify the specific research gap the study aims to address. To indicate how the study addresses the research gap being investigated. To establish the contribution the research makes to the broader field of study it relates to. To signal the organisation of information in the thesis.

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Answer Key
Note: Items in bold and superscript reflect correspondence between columns.

Column A (Extracts from Theses)	Column B (Communicative Purposes)
Research on pollutant emissions of hydrogen-enriched flame has obtained contradicting results. Some researchers found that hydrogen addition reduced CO/CO2 emissions from hydrocarbon flames (Burbano et al., 2008; Schefer et al., 2002) and internal combustion engines (Ji and Wang, 2009; Zuohua Huang et al., 2006), while other researchers found slight increment in CO/CO2 emissions (Lder et al., 1996; Tseng, 2002). Therefore, the effects of hydrogen addition to LPG appear to be far more complicated than expected.	To review and evaluate previous research to identify aspects of the topic that need to be investigated. From the review of the research on pollutant emissions of hydrogen-enriched flame, this study will examine the effects of LPG-Hydrogen fuel.
To date, most of the investigations related to IDF focus on flame appearance, soot loading and thermal performance. There is limited research concerning the effects on these characteristics by using a specially improved fuels mixture.	To identify the specific research gap the study aims to address.
Flame¹ is a special kind of combustion reaction, which can propagate subsonically through space (Pritchard et al., 1977). Flame can also be regarded as a kind of fluid flow with simultaneous chemical reactions taking place. Generally, flame can be classified into […]. In the present study, a particular flame type: inverse diffusion flame (IDF) is studied […]. IDF is believed to have significant potential in domestic and industrial applications².	To identify the research topic¹ and establish its significance². *Note how the research topic moves from the general to the specific: Flame microstructure of a flame a particular flame type: inverse diffusion flame (IDF)
Considering the inevitable CO/CO2 emissions in LPG and difficulties in using pure hydrogen in large scale, it is expected that the mixture of LPG and H2 may balance the properties of LPG and H2 to become a gaseous fuel with high reliability, low pollutant emissions and good thermal performance. The combination […] seems to be a feasible solution to overcoming the drawbacks and to adopting the advantages of both fuels.	To indicate how the study addresses the research gap being investigated.
The overview and the objectives of this study are presented in Chapter 1. Relevant previous research is reviewed and discussed in Chapter 2. Chapter 3 describes the equipment used and operational processes of experiments. Detailed experimental results are presented and discussed from Chapter 4 to Chapter 8. The main conclusion drawn from this study can be found in Chapter 9, together with recommendations emerging from the current study.	To signal the organisation of information in the thesis. Note: Words that highlight organisation of information are in bold.
LPG and H2 mixture, as discussed in previous section, is a kind of fuel mixture with potential advantages as well as uncertainties. The use of LPG/H2 mixture in IDF would be a new goal in scientific research on combustion and flame.	To establish the contribution the research makes to the broader field of study it relates to.
Extracts A-F Adapted from: J. Miao, “Combustion, Thermal and Emission Characteristics of Gas-fired Inverse Diffusion Flames Burning mixed LPG-Hydrogen Fuel”, Ph. D dissertation, Dept. of Mech. Eng., HKPOLYU, Hong Kong, 2015. [Online]. Available: HK PolyU Electronic Theses.

Abstract >> Introduction >> Literature review >> Methodology >> Results >> Discussion >> Conclusion

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Move	Function
The research topic and its significance	To introduce the research topic and establish the contextual background and the significance of the topic being investigated.
Review and evaluation of relevant research	To create a knowledge base of existing research to situate the current study.
Research gap	To identify areas in previous research that have yet to be studied to establish the research gap which the current study addresses.
Objectives of the study	To outline what the study intends to achieve
Contribution of the study	The theoretical knowledge or practical applications of the research that the study contributes to the field.
Overview	An outline of the organisational structure of the theses (what information each chapter will include).

Move	Example Sentences from Engineering theses
1. The research topic and its significance.	*Metallic glasses have received a great deal of scientific and technological interest ever since the first successful synthesis of an amorphous phase in the AU-Si system in 1960[1]. Since then, a large variety of metallic glasses have been developed in both metal-metalloid and metal-metal alloy systems.
2. Review and evaluation of relevant research	**In the past, collision detection for ellipsoids was usually performed by faceting, and then applying a collision package appropriate to general convex polyhedra, such as GJK [20], I-COLLIDE [9], or V-Clip [43]. A drawback with this approach is that accuracy and efficiency are compromised by polyhedral approximation.
3. Research gap	**Regardless of all the advantages and popularity of using quadrics in various applications as we have seen, real-time CCD of quadrics has not been addressed in the literature. Thorough analysis and classification of intersection of general quadrics can be found in classical algebraic geometry e.g. [4, 7, 58] and CAGD [69] […]. These results, however, consider quadrics in the complex (projective, affine or Euclidean) space, and are not applicable to the collision detection problem, for which the analysis must be done in the real affine domain […].
4. Objectives of the study	*** The specific objectives of this study are shown as follows: (1) To examine the feasibility of degrading four typical EDCs (i.e. DMP, DBP, NP, and ATZ) by employing sole-US, sole-UV, and the hybrid process of US/UV. (2) To examine the influence of various parameters on […]
5. The contribution of the study	**We develop an efficient and robust algebraic or numerical solution that achieves real-time performance. Our algebraic approach leads to accurate solutions to the CCD problem for moving quadric surfaces under rational Euclidean or affine motions.
6. Overview	*** This thesis is composed of ten chapters. The present chapter includes the background information, the objectives and the structures of this thesis. Chapter Two provides a comprehensive literature review of related theories and issues. In particular, four involved EDCs as the major probes are introduced in detail, and their basic information, toxicological effects and environmental fate, and previous studies of their degradation are included. In addition, theories of the sonochemical AOT and UV process are summarized and discussed in depth […]. In the last chapter, conclusions of the whole work present in this thesis are summarized […].
* Adapted from: C. Yu. “Prediction and Verification of the Glass Forming Ability in Bulk Metallic Glasses – an Atomistic Approach. Ph. D dissertation, Dept. of Mech. and Biomed. Eng., CITYU, Hong Kong, 2014. [Online] Available: CityU Institutional Repository. Adapted from: Y.K. Choi. “Collision Detection for Ellipsoids and Other Quadrics”. Ph. D dissertation, Dept. of Comp. Eng., HKU, Hong Kong, 2008. [Online] Available: HKU Electronic Theses. * Adapted from: L Xu. “Degradation of Refractory Contaminants in Water by Chemical-Free Radicals Generated by Ultrasound and UV Radiation”. Ph. D dissertation, Dept. Civil and Env. Eng., HKPOLYU, Hong Kong, 2014. [Online] Available: HK PolyU Electronic Theses.

Move	Colour code
1. Review and evaluation of relevant research 2. Research gap	Color Color

Table 3: Linking devices
Function of linking device	Example from a thesis
To compare *Note: Comparison includes contrasting* Examples However*, … Rather, …In contrast, …Conversely, …On one hand, …On the other hand, …In comparison, …Compared to …Another point to consider is …	In the GOA database, each AC may be associated with zero, one or more GO terms. Conversely, one GO term may be associated with zero, one, or many different ACs. ***
To add a comparable point Examples Likewise, again, also	Similarly, for the proteins whose top and 2-nd homologs do not have any GO terms, the third-top homolog was used; and so on until all the query proteins can correspond to at least one GO term. ***
To summarise Examples Finally, …Lastly, …In conclusion, …To summarise, …In summary, …Overall, …The main points are …	Overall, the regular lattice network has the worst performance among the three due to its long average path distance. **
To make one’s argument more specific Examples In particular, … In relation to … More specifically, … With respect to …In terms of …	Communication networks are modeled, analyzed and characterized using complex network parameters. In particular, the impact of network topology, routing strategy and resource allocation on the performance of generic communication networks is studied through theoretical analysis and computer simulation. **
To provide an example Examples For instance, …For example, …this can be illustrated by … namely, …such as …	For instance, in communication networks which we will discuss in detail in the rest of this thesis, node degree represents the number of physical data transmission connections of a computer/router. **
To acknowledge a point and introduce a conflicting or different point Examples Although* …Even though … Despite … Notwithstanding …	Although node degree is a simple measure of in a network, it can be very illuminating. **
To establish cause and effect Examples Therefore, … Subsequently, … Hence, … Consequently, … Accordingly, … As a result, … As a consequence	Consequently, microbubbles containing the vaporized liquid and/or previously dissolved gas will form because of the sufficiently large negative pressures (Adewuyi 2001, Cintas and Luche 1999). ***
* Adapted from: C. Yu. “Prediction and Verification of the Glass Forming Ability in Bulk Metallic Glasses – an Atomistic Approach. Ph. D dissertation, Dept. of Mech. and Biomed. Eng., CITYU, Hong Kong, 2014. [Online] Available: CityU Institutional Repository. Adapted from: J. Wu. “Study of Communication Network Performance from A Complex Network Perspective”. Ph. D dissertation, Dept. Elect and Inform. Eng., HKPOLYU, Hong Kong, 2014. [Online]. Available HKPolyU Electronic Theses. *Adapted from: S. Wan, “Protein Sub-cellular Localisation: Gene Ontology Based Machine Learning Approaches”, Ph. D dissertation, Dept. Elect and Inform. Eng., HKPOLYU, Hong Kong, 2014. [Online]. Available: HK Poly U Electronic Theses.

Table 4: Present perfect tense
Function	Example
To provide information or facts to create a background for the topic	* Simple geometric primitives such as spheres [25], axis-aligned bounding boxes [23, 67], oriented bounding boxes [21], and discrete oriented polytopes [33] have been widely used as bounding volumes for collision detection.
To provide a brief overview of the present state of research	* The bandwidths of C- and L- bands are no longer sufficient to meet the current daily data transmission requirements. To extend the optical bandwidth beyond these two regions, new optical amplifications have been proposed** using […].
To provide a general summary of main trends without identifying a particular article.	Such uncertainties existing in site characterization data have not been accounted for in traditional geotechnical site characterization, which has been** mainly deterministic.
Adapted from: Y.K. Choi. “Collision Detection for Ellipsoids and Other Quadrics”. Ph. D dissertation, Dept. of Comp. Eng., HKU, Hong Kong, 2008. [Online]. Available: HKU Electronic Theses. * Adapted from: K. Huang. “Bayesian Inverse Analysis in Geotechnical Site Characterisation”. Ph. D dissertation, Dept. of Civil and Arch. Eng., CITYU Hong Kong, 2014. [Online] Available: CityU Institutional Repository. *** Adapted from: B. Chen. “Rare Earth Ions Doped Oxide Glass Materials”. Ph. D dissertation, Dept. of Elect. Eng., City U, Hong Kong, 2015. [Online] Available: CityU Institutional Repository.