Kutz M. Handbook of materials selection

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444 HOW TO FIND MATERIALS PROPERTIES DATA

Fig. 2 Searching worksheet.

reasonable time spans and cost budgets. I will add some comments on how to

work with information professionals effectively and some of the electronic re-

sources that are available to help you keep current.

2 THE PROCESS

Deﬁning the Question. What is it you really want to ﬁnd? Too often the

materials engineer limits his or her answer set by asking for what she or he

thinks can be found rather than what he or she really wants and needs. Often

this is due to time restrains because the information or data located in less used

information sources are not as immediately understood or as quickly incorpo-

rated into projects as those found in more familiar resources. These issues need

to be addressed up front in order to get the information you need as quickly as

you need it. Figure 2 shows a simple question or search form to help materials

engineers deﬁne their questions clearly and prepare for the information hunt.

The search request is a sentence or short paragraph that clearly states what

information you need. It helps the engineer to take a moment and write out the

search request. This clariﬁes what information is needed as well as what infor-

mation is already known. In addition, a written search request makes it easier

to communicate with information professionals when their help is needed. Im-

portant terms are those words that will be used to ﬁnd information in indexes

and with search engines. This form is not static; additional terms should be

added as the search for data progresses. Different tools use different terminology

to refer to the same or similar topics. Also, different ﬁelds of study may use the

same term differently. Finally, terminology and how it is applied changes over

the years. In most databases, the indexing is not updated, so the searcher needs

to be familiar with all possible indexing choices. Here are some examples of

these issues.

2 THE PROCESS 445

Example 1: Spelling Variations

Recently, a scientist wanted information about ‘‘eschelle spectroscopy.’’

When only nine abstracts were obtained with that phrase, I suggested we

look at the spelling of ‘‘eschelle.’’ Two variant spellings were in one of

the nine abstracts retrieved. ‘‘Eschelle’’ was in the title and ‘‘echelle’’ was

in the indexing. With the alternative spelling over 100 citations were found

allowing further speciﬁcation to include ICP (inductively coupled plasma)

as a technique. Twenty-one citations were found with very speciﬁc infor-

mation relevant to the work being done.

Over the years, these types of instances have shown me to always think

broadly when dealing with terminology or important information will be

missed, especially in cross-disciplinary searches. In the print world, these

spellings might have been relatively close to each other in the index, and

serendipity would have played its role in ﬁnding information. In the online

world the searcher has to think broadly enough to make up for this loss of

serendipity. Alternative spellings, abbreviations, and acronyms should al-

ways be included in a search in order to retrieve good resources.

Example 2: Terminology Changes over Time and Emphasis

Varies by Discipline

Biomaterials is a cross-disciplinary area of research. To be effective in

developing materials, the materials engineer may need to refer to the med-

ical literature, chemical databases, and biological resources as well as the

more traditional engineering resources. How many resources might be

needed will vary depending on the nature of the search and how compre-

hensive the results need to be. Beginning investigation may not need mul-

tiple sources or databases. Dealing with a process or material that may

eventually need to be patented will deﬁnitely require searching in multiple

sources to ﬁnd prior art.

The concept of biomaterials seems to be well deﬁned in the engineering

community today. The Biomedical Engineering Handbook states: ‘‘A bio-

material is used to make devices to replace a part or a function of the body

in a safe, reliable, economic, and physiologically acceptable manner.’’

Another current deﬁnition of biomaterials is: ‘‘An engineering material

suitable for use in situations where it may come into direct contact with

the internal tissues of the body. Sometimes, biomaterials is used to refer

to biological structural materials.’’

Notice the difference in emphasis on

how the material will be used. Biomaterials have been in use since the

1800s. As late as the 1970s biomaterials were more often referred to under

the heading of biocompatible materials.

‘‘Synthetic biomaterials can be

referred to as biomedical materials to distinguish them from naturally oc-

curring biomaterials.’’

The medical community refers to biomaterials as ‘‘any substance (other

than a drug) synthetic or natural, that can be used as a system or part of

a system that treats, augments, or replaces any tissue, organ or function of

the body.’’

Currently the medical community tends to use speciﬁc names

for types of biomaterials as well as the applications of these materials

rather than the general term biomaterials.

446 HOW TO FIND MATERIALS PROPERTIES DATA

The chemical community, as usual, focuses on the compound or class

of materials such as polymers, ceramics, and metals with biomaterials or

biomedical materials being considered a use rather than a type of material.

All of these differences need to be taken into consideration as the lit-

erature is searched. In this example the following terms would be included

as possible search points: biomaterial(s), biomedical material(s), biomedi-

cal device(s), synthetic biomaterial(s), biological structural material(s), as

well as more speciﬁc terms and chemical names relating to the speciﬁc

interest.

One area where differences in terminology are deﬁnitely a factor is in

chemical names. This means it is a good idea to identify terms like the

Chemical Abstracts Service Registry Number (CAS RN), common names,

trade names, and IUPAC or CAS names. Which of these names you know

will often help you choose what tool to use to ﬁnd the information or data

you need. Again, variations on the chemical names will need to be added

as the search progresses. Polymers is one area where nomenclature is very

tricky, partly due to the large number of trade names as well as to seem-

ingly insigniﬁcant changes in the chemical makeup of the polymer.

Example 3: Chemical Compounds and Chemical Classes

Polyethylene is listed as a nonaromatic hydrocarbon backbone polymer in

the Physical Properties of Polymer Handbook.

A slight name variation is

noticed in the online edition of the CRC Handbook of Chemistry and Phys-

ics—poly(ethylene)—with a broader class name given as polyalkenes.

These differences are not critical in the paper world but might be in an

electronic database. Chemical Abstracts has called this material by several

names over the years. In the 8th Collective Period it was referred to as

‘‘ethylene, polymers.’’ Starting with the 9th Collective Period it has been

referred to as ‘‘ethene, homopolymer.’’ The registry number 9002-88-4 has

over 4500 alternative names (many trade names). There are also 84 deleted

registry numbers (or compounds that at one time were considered unique

and have since been reviewed and found to be ‘‘ethene, homopoly-

mer.’’) There are at least 49 ﬁles available on STN International (a vendor

of databases with scientiﬁc bibliographic and numeric information; more

fully described at the end of the chapter), a searching system that has

information about the compound with registry number 9002-88-4. Each of

these ﬁles has different methods of inputting chemical and material names,

and each will provide different types of information. BIOSIS (the online

database devoted to biological literature, described in depth later in the

chapter), when searching for ‘‘polyethylene’’ as a controlled term, has 997

(search done on 4/28/01) citations. However, on the STN system, registry

numbers have been added to the BIOSIS indexing for chemical compounds

listed in the title of the article. Using the registry number as a search term

yielded 2706 additional citations. When these citations were reviewed, it

became quickly obvious that trade names were often used to refer to the

polymer in the BIOSIS ﬁle. Without searching the registry number, im-

portant information would have been missed and the materials engineer

might have missed, an important possible use for the material being studied

2 THE PROCESS 447

or the fact that some other company has already gotten approval for clinical

trials with a product. Missing information in either case will cost the com-

pany.

Locating Needed Information. Once the research area has been well de-

ﬁned, it is time to move onto the search strategy. There are three major decisions

that need to be made. First, is background information needed? If so, what are

the background resources that should be consulted to gather basic information

relating to the project? If background information is not needed, it is possible

that the appropriate background resources will provide leads as to what databases

should be investigated.

Second, what databases (deﬁned as a searchable source of information in

paper or electronic format including data compilations, handbooks, and literature

resources) will be appropriate to ﬁnd the information you need. Do not limit the

research to known databases in engineering. Materials science is cross discipli-

nary in nature. Literature databases in many other ﬁelds such as biology

(BIOSIS), physics (INSPEC), medicine (MEDLINE) and chemistry (Chemical

Abstracts) as well as Engineering Index (COMPENDEX) should all be con-

sulted. The number of databases that need to be accessed depends on how com-

prehensive the information needs to be. These databases are discussed in more

detail later in this chapter. Materials that may end up in a patent need to be

researched in great depth using both print and online databases. Special attention

to patent resource ﬁles such as Derwent and the U.S. Patent ﬁles will be needed

when preparing for patent processes.

When dealing with data sources (handbooks, electronic databases, etc.), it is

also wise to consider not only those that are well know in materials science but

also those in related disciplines. Though the data needed may be in different

formats or measured in different manners, they can still be useful when designing

new materials. Chapter 16 discusses data sources and search strategies that vary

depending on the type of data needed in considerable depth.

Third, are there any limitations that need to be considered before going into

the resources? Often researchers provide themselves with false limitations such

as:

If the data is not available in an electronic format, then it doesn’t exist.

Anything published before 1960 is not accurate.

One example is the vast amount of information available through Gmelin, short

for Gmelins Handbuch der Anorganischen Chemie, which contains data on in-

organic compounds and materials collected and published from the 1800s.

Though the data are old, and further testing may be needed with today’s ana-

lytical tools, the data are well researched in considerable depth and are some-

times the only data available. This tool has been made easier to use with the

advent of Crossﬁre, which provides an extensive index with some of the property

information in an electronic format. This tool may provide helpful starting points

for more in-depth investigation. For example, Gmelin has six volumes dealing

with molybdenum and compounds of molybdenum. Additional information can

be found in other volumes as well. The 4-page section in the main volume

448 HOW TO FIND MATERIALS PROPERTIES DATA

(published in 1935) detailing the thermal properties of elemental Mo included

data on the speciﬁc heat measured from

⫺253 to 1500⬚C. Referenced data for

these results go back to Annales der Chimie et de Physique in 1840. The Gmelin

database, as loaded on STN, cites 44 measurements of heat capacity at a constant

pressure and 10 measurements of heat capacity at a constant volume. One of

the later measurements comes from Physical Review B, vol 44, 1991. Over 150

years of literature is covered in this database.

Limitations that will be helpful include project deadlines, details about the

physical state of the materials being researched, material characteristics and

physical properties that are critical to the project goals, and cost limitations.

Deadlines and cost limitations become very important when the information

specialist is consulted. Generally speaking the sooner the deadline the more

expensive the search process will be.

Using Best Known Resources First. Taking the time to be open to different

possibilities means the results of the process may be very different than the

expected ‘‘correct answer’’ foreseen at the beginning of the process. Also, there

are a vast number of data resources to be considered, each with it own quirks.

A busy materials engineer does not have the time to learn how to use them all.

Take a look at Chapter 16 to get an idea of the many databases and information

sources available. The best and most knowledgeable materials engineer cannot

possibly know more than a few of these resources well. However, now that many

handbooks have electronic versions and databases are developing more user-

friendly search interfaces, it is possible to have access at your desktop to many

familiar handbooks and databases. Searching for clues to information not as

readily available can be done without leaving your ofﬁce by using both paper

and electronic resources.

Each materials engineer should develop his or her own desktop library. This

collection will be a combination of print and electronic resources with which

the materials engineer is familiar. Electronic versions of familiar resources

should be used when the electronic interface adds to the value of the resource

or space does not allow for the printed item. The desktop library should be

considered both a fast answer resource as well as a place to ﬁnd more clues to

solve the physical property logic puzzle. The desktop library should contain at

least one major handbook as well as some specialized handbook or data com-

pilations. How many of these resources are used will depend on the space and

funds available.

With the advent of online encyclopedias, the Desktop Library can contain a

good resource for background information. Look at the electronic version of

Ullmann’s Encyclopedia of Industrial Chemistry and Kirk-Othmer Encyclopedia

of Chemical Technology as possible resources. Access to the primary literature

can be gained through full-text journals with or without use of indexing and

abstracting tools. Two useful journals, now available full text are Journal of

Physical and Chemical Reference Data (http://ojps.aip.org/jpcrd/) and Journal

of Chemical & Engineering Data (http://pubs.acs.org/journals/jceaax/index.

html). Both of these titles have been terriﬁc data sources for many years.

Three hard copy handbooks (which can also be accessed electronically) that

provide both basic information and leads to more extensive resources come to

2 THE PROCESS 449

mind—Perry’s Chemical Engineers’ Handbook, Engineering Handbook by Dorf,

and CRC Handbook of Chemistry and Physics. Several materials-related hand-

books are also useful resources—Materials Handbook by Brady and Clauser

and the CRC Materials Science and Engineering Handbook. These are only a

few of the titles available. The materials engineer should ﬁnd the handbook(s)

that ﬁts his or her needs best. Once the more general handbooks have been

selected, more speciﬁc subject/project-related handbooks are helpful. For ex-

ample, an excellent resource in physical property information for polymer sci-

ence is the Physical Properties of Polymers Handbook by James E. Mark,

published by the American Institute of Physics. Notice that the handbooks men-

tioned are from a variety of disciplines that might be of use to a materials

engineer.

The resources chosen should include basic information needed on a regular

basis as well as charts and tables of information that might prove useful. For

example, the CRC Handbook of Chemistry and Physics has very familiar tables

of basic property information for organic and inorganic materials. But, unused

by many, is the wealth of tables on many topics of interest to the materials

engineer. I have already mentioned the Glass Transition Temperature for Se-

lected Polymers. This table, by Robert B. Fox, has properties that were deter-

mined for the purpose of generating this table. Many tables are compilations of

data from several sources, and the editors of the handbook are careful to note

what resources were used. A good example of this is another table in the same

section—Dielectric Constant of Selected Polymers. This table references three

sources:

1. Gray, D. E., Ed., American Institute of Physics Handbook, 3rd ed.,

McGraw-Hill, New York, 1972, p. 5–132.

2. Anderson, H. L., Ed., A Physicist’s Desk Reference, American Institute

of Physics, New York, 1989.

3. Brandrup, J., and Immergut, E. H., Polymer Handbook, 3rd ed., Wiley,

New York, 1989.

This reference list provides several pieces of information. First, it provides ref-

erences to sources that may have more detailed information than that provided

in this table (including the analytical methods used to generate the data). Second,

they state the approximate ‘‘age’’ of the information. Because the dates are all

prior to 1989, it becomes probable that additional information is available in the

primary literature, in more current handbooks such as the Physical Properties

of Polymers Handbook mentioned earlier, or in later editions of the handbooks

referenced. Third, the references provide you with evaluative information. Know-

ing that the data has been in the published literature adds additional credence

similar to peer review for other types of scientiﬁc literature. This is critical, as

many online web pages with physical data on various compounds and materials

do not tell you how the information is obtained, what the experimental conditions

are, or even the purity of the material being tested. Starting with the known

resource such as a favorite handbook, a physical property database, or a full-

text journal, can lead to quicker results and very complete answers. With so

450 HOW TO FIND MATERIALS PROPERTIES DATA

many handbooks and data compilations available at the desktop, it is important

for the materials engineer to make the following decisions on what to include

based on the following recommendations:

Include materials in your desktop library that you will use often. Know how

to use your desktop library well.

Include items that have the type data or information needed routinely. Find

out what is included in each resource as well as what limits (i.e., only data

from patents is included) have been placed on inclusion.

Include items where access methods, such as indexing, table of contents, and

online search options, are easy to use.

Include authoritative resources with good literature references and clearly

noted experimental conditions.

Going beyond Desktop. Once the familiar resources have been exhausted,

it is time to consider outside help. Obviously, if you found the information you

need and you are relatively certain you do not need additional veriﬁcation, the

search can stop at any time. However, if the desktop library has not led to the

information you need or the project is being considered for publication or pat-

enting, it is time to see the information expert in your organization.

The structure for getting information varies in each organization. It is impor-

tant to understand the information climate or your organization. Some expect

the materials engineer to ﬁnd it all on their own. Some feel looking for infor-

mation is not an effective use of the materials engineer’s time and expects all

such research efforts to be turned over to an information specialist. Most orga-

nizations have information centers, libraries, or reading rooms. Smaller com-

panies or colleges may have limited access to information resources and external

libraries or information brokers must be used. Many of the larger organizations

will have information specialists or librarians. Smaller organizations may not

have specialists in the area you are working, however, information professionals

are all specialists in data organization and retrieval. So, even if they do not have

the subject expertise you would like, they will often be able to help you use the

tools effectively.

When to use these resources will depend on the information need. Find out

what is preferred in your organization and do not limit your exploration to what

the folks in your direct department do unless it is the best way for you to ﬁnd

the information you need. Often there are resources outside the department that

will also help. In some places use of these external resources are not encouraged

as there is a cost attached. In that case, try to weigh what the cost will be if the

information needed is not found—e.g., millions of dollars spent on developing

a product that someone else patented 2 years ago—against the cost of a good

information search.

Many standard resources are now available to the engineer electronically and

can be incorporated into the desktop library discussed previously. A cautionary

note here. Make sure proper training on the use of even the basic resources is

taken. As mentioned before, even the simplest of resources could have a wealth

of information an engineer is not aware of because they have not used it to its

fullest capacity. A tool you have used throughout your professional life may

2 THE PROCESS 451

have more information than you thought or may be used in different ways for

better results. As electronic resources become more prevalent, the method of use

may change from year to year, and a resource you knew how to use last month

may have a new interface this month. The information professional is the expert

on how to use information products. Information specialists and librarians gen-

erally enjoy showing the researcher and engineer how to use resources to their

fullest capabilities. Many organizations will have routine training opportunities

for those resources that are of the most use to their employees. Taking the time

to learn these resources well will not only save you considerable amount of time

later but the training opportunities will give you a chance to get to know the

information staff at the organization. Then, when you need their help, they may

already know what you are working on. This can speed up the process consid-

erably. One additional note, some engineers are not comfortable with sharing

their ideas at an early stage. Be assured information professionals know that

conﬁdentiality is an important part of their work. Your queries will not be shared

with others.

Find out who the information gatekeeper is within your immediate organi-

zation. Sometimes there is a person who enjoys working with information who

can guide you to the best resources and the best information specialist or li-

brarian for your speciﬁc needs. In smaller organizations the information gate-

keeper may indeed be the only information specialist available.

Always make use of internal resources ﬁrst. Use the corporate library or

information center as the ﬁrst stop after exhausting your desktop library and

your department’s information gatekeeper. Do not make the web your ﬁrst

stop outside your department! This does not mean to ignore valuable resources

that are available electronically through the Internet, such as the NIST databases

and the many ﬁne reference tools available. Rather it means use known re-

sources, including your organization library and librarians (information center

and information specialists), and purchased and attributed data sources accessed

through the Internet before searching the highly disorganized web. The web

contains vast amounts of information. However much of it has no attribution

and little of it is organized so that information can be easily found. Anyone can

post a page to the web for any reason. No quality check required. One excellent

Internet resource is product information available in fact sheets and material

safety data sheets (MSDS). As these are part of how a company markets its

items, they should contain reliable information. At my institution, I tell students

that when it is time to use the web, start at the library’s home page where the

librarians have already sorted through the web resources available and found

some of the better ones to recommend. Also, the home page is where links are

made to those electronic resources with web interfaces that the library purchases

for students and faculty use.

After exhausting internal resources, ﬁnd out what external organizations your

company uses at a fee to get the information you need. If your organization has

a library or information center, this may be transparent, i.e., the information

center will provide the information to you by going to an outside organization.

These services are called InterLibrary Loan (ILL) or document delivery by the

library world. If your organization does not have such a service, it may have

purchased information research skills through information consultants or bro-

452 HOW TO FIND MATERIALS PROPERTIES DATA

kers. If it has done so, these consultants are most likely aware of the general

needs for projects within your organization and may have specialized training

in retrieving information applicable to your needs.

It is a good idea to determine what local colleges or universities have agree-

ments with your organization that will allow you to use their collections. Unless

your have a large library, browsing through a university research collection can

be a fruitful way to gather information. For a small organization without internal

information resources, local academic libraries are critical.

Academic libraries are the storehouse of information for the research com-

munity. However, this does not mean this information is accessible to every one.

Public colleges and universities usually have some mandate to provide access to

their collections and perhaps some services to residents of the state. What the

limits of this access are will vary. Private academic communities do not have

any obligation to provide such access, although many do. In either case, access

methods and procedures will vary:

1. Check with the company library to ﬁnd out if access to collections has

been purchased. Academic libraries may be willing to allow members of

local organizations to check out materials from their library upon pur-

chase of a library card. Also, many companies do have ILL agreements

that allow the company library to request copies of materials.

2. See if the reference services are available to noncommunity members.

Generally a limited amount of reference service is available to the public,

but this is not always the case. Reference staff like to help people ﬁnd

information. Being polite and friendly, asking interesting questions, un-

derstanding you are a guest, using services during slow times of the

academic year, as well as being from an organization that supports the

university can all mean your reference queries are taken seriously.

3. Determine what resources are accessible by noncommunity members. It

used to be that anyone allowed in the door could use the paper copy

Engineering Index. Now that the tool is in electronic format there may

be restrictions on use for noncommunity members due to licensing agree-

ments or searching costs.

4. Some academic libraries offer a fee for service arrangement. These can

be very important to small companies. The costs are usually set up to

recover any out-of-pocket expenses as well as some amount for the li-

brarians’ time.

5. Be aware that collections, electronic resources, and services cost money.

If your company is relying on a local academic library, remember to offer

assistance ﬁnancially. This can often be done through Friends of the Li-

brary organizations, paying for research services, or by providing research

funding (though this route will not get funding directly to the library).

Evaluating Data/Information Resource. One of the themes running

through this chapter has been quality of information resources. This quality is

seen by both the way the resources are organized and the value and quality of

2 THE PROCESS 453

information or data retrieved from the resources. Knowing how to evaluate in-

formation for quality is critical. It is important because bad data/information

leads to poorly designed materials and bad products. For example, the shuttle

Challenger disaster could have been avoided if better data on the stress and

temperature factors affect the rubber rings had been incorporated into the design

speciﬁcations.

There are several ways to evaluate the information you ﬁnd. First, look at the

quality of the resource being used. Handbooks that have been around for many

editions and printings will generally have time-tested information. Property data

from a well-know handbook is always better than a value found on some web

page without any attribution. Peer-reviewed journal articles may provide better

data than trade publications. Second, data that has experimental parameters de-

ﬁned is always better than ‘‘naked’’ information. The more known about how

the information was collected the better. Third, if the person preparing the data

source has not provided information on how it was collected or who measured

it, it should only be used with caution. Fourth, use caution with information

obtained from web pages. Remember that anyone can put up a web page. There

is no requirement that data on a web page be accurate. Check the page out. Is

there an author speciﬁed? Was the information put up by an unbiased organi-

zation? If the page is from a university, is the author a researcher or a student

doing a class project? If the information is from a company, is it trying to sell

you something?

It is the materials engineer’s responsibility to evaluate the information. The

best scenario is to have multiple sources of information to quality check. This

is rarely possible, and, sometime when it is, further checking many ﬁnd that the

data from multiple secondary resources came from the same primary resource.

So the data and information must always be used within context and with care.

Sometimes that means starting again because the data or information is suspect.

Redeﬁning the Question Using New Information. Starting again does not

mean starting over. Usually there has been some information gathered that allows

the materials engineer to reﬁne the search question either more broadly or more

narrowly. If no data has been found, broaden the topic and see if related infor-

mation can be used. Can other properties be used to provide information if the

speciﬁc one needed is not reported? When too much information has been found,

narrow the topic wisely. Again, do not assume you want to narrow the scope by

using only familiar resources. Sometimes the narrowing needs to be done by

using resources outside the ﬁeld that specialize in the information needed. Re-

member information specialists and librarians are experts in reﬁning the search

question.

Knowing When Information Gathered Is Enough. Unlike a logic puzzle,

data research does not always have an answer. Sometimes there is no data. For

the researcher trying to delve into a new area, this might be wonderful. For the

materials engineer trying to modify an existing material, this can be annoying.

However, after you have broadened the search, after you have found related

information but not exactly what you want, and after an information professional

states the information does not appear to be the published literature, then it is