Use Boolean Searching to find what you want

Main Boolean Characters AND, NOT, OR Parentheses (or " ")

Proximity character (usually NEAR) Wildcard character (* or !)

If I walked into a crowded room at an AIChE meeting and asked, "how many people here know Boolean Searching?," a few people would probably raise their hands. And this may be for a very good reason - we are engineers, not librarians. But with the rise of the Internet and continued development of new and exciting Web sites and search engines for engineers, Boolean searching is something that all engineers should know something about.

Boolean searching is named after 19th-century mathematician George Boole. Boole created the branch of math known today as symbolic logic. Boolean searching is done by the use of symbols, and also is very logical.

When you log on to a search engine to search the internet (for more information see "Search the Internet More Efficiently," CEP, February 2001, p. 55) you usually simply type in words (the "search string") that you want to find. For instance, your search string might be "PET polymer." The search box usually doesn't care about how many words you put in or what order they are in - it simply searches the internet looking for the words you put into the box. Boolean searching, on the other hand, adds logic to the search string.

It should be noted that not all search engines accept Boolean searching, and most have a separate page specifically for "professional searchers" (i.e. those who know Boolean searching) that uses either partial or full Boolean searching. This is because in the past only professional searchers used Boolean searching. But it can be immensely helpful for engineers looking for information on the Internet. My favorite site that accepts Boolean Searching is ixquick (http://ixquick.com/). It is a meta-search engine, which means it will automatically search a lot of other search engines (such as Yahoo, Lycos, and others).

The Mechanics

Boolean searching simply uses logical words or characters (called "operators") to tell the search engine what to do with the words you enter. A simple example is "AND." If I enter a Boolean search for cat AND dog, the search engine will use the Boolean character AND to search for both cat and dog, and return pages that only include both of the words.

Similarly, "OR" can be used to find either of the words. For instance, cat OR dog only returns pages with either cat or dog on the page.

Finally, the third basic Boolean command is "NOT", which searches for the first word, but doesn't show any results that include the second. The search cat NOT dog will find pages that include cat, but none that include dog).

From these three choices (AND, OR, and NOT), it can be seen that AND is the most inclusive, and NOT is the most exclusive. It should be noted that many search engines will accept "+" or simply a space instead of AND, and "-" instead of NOT.

After you begin using these three basic Boolean search characters, you can refine your searches even more by adding parentheses and proximity operators. Parentheses (quotation marks " " in some search engines) do the same thing as in math - they group objects together. For instance, I can do the search (cat AND dog) NOT (bird OR fish). This will bring back all pages that contain the words cat and dog, but nothing that contains either the word bird or fish. Parentheses can add a lot of power to your Internet searching.

After you learn to use parentheses, you can move a step further by adding proximity operators. The most common proximity operator is NEAR. It will only find pages that have the words you type near each other. The exact definition of "near" varies from search engine to search engine - anywhere from 2 to 25 words apart is typical. For instance, (cat NEAR dog) will give you pages that have the words cat and dog in close proximity to each other in the text.

If you still cannot find what you are looking for after using all of these operators, try using the wildcard character. This character, which can be a ! or a *, depending on the search engine, tells the search engine that anything after that character in the word is acceptable.

For instance, "do*" will find the word dog (it will put a g in place of the *). But this will also find other words which start with "do," including doing, doer, does, doze, dozen, dork ... So you can see that if we are searching for "dog," this is a bad use of the wildcard character.

A good use of the wildcard character is when you don't know what tense or plurality the word is in. For instance, a search for "dog*" will bring back dog, dogs, doggie, etc. This may increase your chances of finding the resulting page that you are looking for.

While there are many other possible operators, these are the main ones that Boolean searching uses. Depending on the search engine, there will be many variations of this (for instance, one search engine uses NEARS to mean within 5 words). But the main idea of Boolean searching is the same - adding logic to the search string, so you can get better searching results.

With the use of Boolean searching, you should find that sifting through all of the information available on the Internet becomes easier and less time-consuming. Good luck, and good Boolean searching!

Excercise

Write a search string to find information about the following:

1. 12-stage distillation column (that exact phrase), using acetone or ketone, but nothing that has to do with DuPont.

2. Valve (or valves), for water, at a 200 psi pressure drop. 3. a vapor-liquid equilibrium chart for methanol-benzene

[Author Affiliation]

S. THALER has had considerable experience in the internet arena, culminating in his current position as Producer at eBusiness consulting firm Imaginet(division of J. Walter Thompson), and member ofthe Lutheran Social Services Information Technology Advisory Board. Prior to that, he developed an online research portal for Teltech.com, which won the CIO magazine's 50/50 Intranet awards. He is also a lead instructor with the Breakthrough Corporate Results program (http://www.BRCOR.com), and is a board member of ThermoDynamo (http://www.thermodynamo.com), an Engineering and IT Recruiting firm. Slava has a BS in chemical engineering from the University of Minnesota and is Chair of the Twin Cities AIChE local section. He can be reached by phone at (612) 242-4536 or by e-mail at SlavaThaler@yahoo.com