Numerical Databases

Factual databases mainly contain alphanumeric data on chemical compounds. In contrast to bibliographic databases, factual databases directly describe the objects primary data on chemical compounds) and provide the required information on them. Factual databases can be divided into numeric databases, metadatabases, research project databases, and catalogs of chemical compounds. 

Numeric databases primarily contain numeric data on chemical compounds, such as physicochemical values and the results of series of measurements. Therefore, the files correspond to printed tables of numeric property data. Since the attributes of numeric data are different from those of text data, the search has to be managed... 

Typical numeric databases are Beilstein, Speclnfo, DETHERM, and the Cambridge Structural Database. 

Another numeric database including bibliographic information is DETHERM. 

ICSD is a numeric database with 65 000 inorganic crystal structures (December,... 

GenBank [32] is a text-numeric database of genetic sequences with more than 28 billion bases in 22 million sequences (January, 2003) from genetic research. The collection of all publidy available sequences is annotated with information such as sequence description, source organism, sequence length, or references. The database, estabhshed in 1967, is updated daily and produced by the National Center for Biotechnology Information (USA). 

The protein sequence database is also a text-numeric database with bibliographic links. It is the largest public domain protein sequence database. The current PIR-PSD release 75.04 (March, 2003) contains more than 280 000 entries of partial or complete protein sequences with information on functionalities of the protein, taxonomy (description of the biological source of the protein), sequence properties, experimental analyses, and bibliographic references. Queries can be started as a text-based search or a sequence similarity search. PIR-PSD contains annotated protein sequences with a superfamily/family classification. 

If users are inexperienced in searching for information, they should first consult search engines, meta-databases or portals (Table 5-6). Searchers who are familiar with databases may consult known databases (numeric databases, bibliographic databases, etc.) directly, being aware that they might miss new data sources (see Section 5.18). The reliability and quality of data are only given in peer-reviewed data sources. 

Numeric. Researchers routinely use reported numeric measurements and data in thek work. Handbooks have been the primary source for locating this type of information, but numeric databases are now increasing in availabiUty. Advantages of searching numeric databases on-line include ease of use, dkect access to desked data, and abiUty to manipulate the information in the answer set. 

TDS UMERICA. This is another source for numeric databases (58). This company provides different on-line databases and software for chemistry, engineering, and environmental data. A summary of its databases is contained ia Table 7. 

OtherD t b ses. Available from different vendors (Table 8). For example, the researcher can obtain physical properties by usiag the Merck Index Online or the Dictionary of Organic Compounds available by Chapman and Hall Chemical Database. In DIALOG, numeric databases are collected under the name of CHEMPROP. 

CS4JSI/SND. The Canadian Scientific Numeric Database Service (CAN/ SND) is provided by the Canada Institute for Scientific and Technical Information (ClSTl), a division of the National Research Council of Canada. It contains 140,000 ir spectra of 96,000 compounds. Entries consist of peak locations and some intensities. This system is searchable on-line using the SPIR (Search Program for Infrared Spectra) (85). Table 9 summarizes the available databases in the area of spectra. 

Integrated Systems. Until recently, each of the numerous databases and sources of information available to chemists and technologists had to be searched iadividually, and selected results either ptinted for file storage or downloaded to an ia-house or private computer system for easy future access. 

The percentage of word-oriented databases continues to increase at a faster pace than numeric databases. The number of image databases was 358 in 1992, greater than twentyfold increase from 1989. Audio databases rose from 1 in 1988 to 109 in 1992. A breakdown of the subclasses within word-oriented databases is given in Table 3, showing that full-text databases have surpassed bibhographic ones. Directory databases are the third most numerous. 

A failure modes and effects analysis delineates components, their interaction.s ith each other, and the effects of their failures on their system. A key element of fault tree analysis is the identification of related fault events that can contribute to the top event. For a quantitative evaluation, the failure modes must be clearly defined and related to a numerical database. Component failure modes should be realistically and consistently postulated within the context of system operational requirements and environmental factors. 

Type in-house numerical database with editor for the construction of a customized database... 

Wood, G.H., manager, CAN/SAN Scientific Numeric Databases, Canada Institute for Scientific and Technical Information, Ottawa, Canada. 

Thermoplastic Polymers. Most thermoplastic polymers are used in high-volume, widely recognized applications, so they are often referred to as commodity plastics. (We will elaborate upon the distinction between a polymer and a plastic in Chapter 7, but for now we simply note that a plastic is a polymer that contains other additives and is usually identified by a variety of commercial trade names. There are numerous databases, both in books [1] and on the Internet [2], that can be used to identify the primary polymer components of most plastics. With a few notable exceptions, we will refer to most polymers by their generic chemical name.) The most common commodity thermoplastics are polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) and polystyrene (PS). These thermoplastics all have in common the general repeat unit -(CHX-CH2)-, where -X is -H for PE, -CH3 for PP, -Cl for PVC, and a benzene ring for PS. When we discuss polymerization reactions in Chapter 3, we will see that all of these thermoplastics can be produced by the same type of reaction. 

Numeric. Researchers routinely use reported nunierie measurements and data in their work. Numeric databases include the Beilstein Handbook of Organic Chemistry, ihc Gmelin Handbook of Inorganic and Orgunomelallic Chemistry, properly daia networks the Materials Property Data Network Inc. (MPDt and Chemical Property Data Network (CPDNtl. and TDS NUMERICA. 

Spectra. The ability to consult collections of standard spectra is crucial in the analysis of unknown compounds A long history of data collection efforts has been aimed at these applications. Among ihe best known of the published handbooks arc the Sadtlcr Spectral Data Sheets, which include ir. Raman, and nmr spectra. On-line sources include the Chemical Information System. Speclnlo. and The Canadian Scientific Numeric Database Service tCAN/SND). 

Third Chemical Congress of North America, American Chemical Society, June, 1988, Toronto, Canada, Herman Skolnik Award Symposum, Scientific Numerical Databases, Present and Future. 

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