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Tham khảo tài liệu 'a heat transfer textbook - third edition episode 3 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Part vi Appendices 689 A. Some thermophysical properties of selected materials A primary source of thermophysical properties is a document in which the experimentalist who obtained the data reports the details and results of his or her measurements. The term secondary source generally refers to a document based on primary sources that presents other peoples data and does so critically. This appendix is neither a primary nor a secondary source since it has been assembled from a variety of secondary and even tertiary sources. We attempted to cross-check the data against different sources and this often led to contradictory values. Such contradictions are usually the result of differences between the experimental samples that are reported or of differences in the accuracy of experiments themselves. We resolved such differences by judging the source by reducing the number of significant figures to accommodate the conflict or by omitting the substance from the table. The resulting numbers will suffice for most calculations. However the reader who needs high accuracy should be sure of the physical constitution of the material and then should seek out one of the relevant secondary data sources. The format of these tables is quite close to that established by R. M. Drake Jr. in his excellent appendix on thermophysical data A.1 . However although we use a few of Drake s numbers directly in Table A.6 many of his other values have been superseded by more recent measurements. One secondary source from which many of the data here were obtained was the Purdue University series Thermophysical Properties of Matter A.2 . The Purdue series is the result of an enormous propertygathering effort carried out under the direction of Y. S. Touloukian and several coworkers. The various volumes in the series are dated since .
