The goal of an engineering abstract is to efficiently and concisely express the purpose and results of your paper. Readers look at the abstract because they are in search of answers, and the abstract allows them to know if your paper is of use to them or not. If the research problem is presented but not the results that address the problem, the reader will not read the article and will search elsewhere. By including the overall results in the abstract, the reader gets a feel for the article and if it is worth reading.
Abstract follows a structure of introductory sentence, a methods sentence, 2-3 sentences of key data points and a conclusion sentence on the overall result. First, there should be an introductory sentence on the research that is needed in a specific area or a problem that needs to be examined. It should introduce the study; that is, the plan to address the problem. Next, the abstract should also include a sentence on data such as tests, samplings, survey results, etc. Following the method of study, a two to three sentence discussion that includes key data points of the study would be helpful to the reader. The abstract should not include mathematics or citations (remember–it is a summary, not a detailed explanation). The conclusion of the abstract should share the overall results from the study. An abstract should stand on its own, i.e. the reader should be able to understand the content of the paper just from reading the abstract.
For an example of how to write an abstract, see the sample document below (Fig. 3.1). Notice the length and placement of the abstract. Also notice that at the end of the abstract are a list of keywords that would be used in a search engine to find the article.
The introduction could be very lengthy or quite short depending on how long and involved the research is. At times, an introduction could include an abbreviated literature review or history of the project. If the research is a part of a bigger endeavor, the entire study could be briefly discussed and referenced.