ASTM_D_3947_-_92_scan.pdf

ASTM D3947 92 0759510 0535359 256=(CTb Designation:D 3947-92 AMERICAN SOCIETY FOR TESTING AND MATERIALS 1916 Race St Philadelphia,Pa 19103 Reprinted from the Annual Bwk of ASTM Standards.Copyright ASTM If not listed in the current combined Index,will appear in the neb edition.Standard Test Method for Specific Heat of Aircraft Turbine Lubricants by Thermal Analysis This standard is issued under the fixed designation D 3947;the number immedittely following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parenthescs indicates the year of last reapproval.A superscript cpsilon(cl indicates an cditorial changc sincc the last rcvision or reapproval.1.Scope 1.1 This test method covers the determination of the specific heat of oil by differential scanning calorimetry(DSC).1.2 The values stated in SI units are to be regarded as the standard.The values in parentheses are for information only.1.3 This standard does not purport to address all of the safety problems,if any,associated with its use.It is the responsibility o f the user o f this standard to establish appro-priate safety and health practices and determine the applica-bility o f regulatory limitations prior to use.For a specific hazard statement,see Note 1.2.Terminology 2.1 DtJnition:2.1.1 speciJic heat,s,n-a measure of the amount of energy required to produce a given temperature change within a unit quantity of that substance.3.Summary of Test Method 3.1 Values for specific heats of oils are determined by the following two-step procedure.The differential scanning cal-orimeter is programmed first to heat an empty,unsealed sample pan over the desired temperature range while moni-toring the heat supplied as a function of temperature.The program is repeated for the hermetically sealed sample pan containing a weighed sample of oil.The specific heat of the oil is calculated froh the difference between these two sets of measurements.3.2 A pure material with published specific heat values(for example,diphenyl ether)is used as a calibration stan-dard.Calibration scans are made under the same experi-mental conditions as are used for the oil samples.4.Significance and Use 4.1 The specific heat or heat capacity of a substance is a thermodynamic property.It is used in engineering calcula-tions which relate to the manner in which a given system may react to thermal stresses.5.Apparatus 5.1 Diflerential Scanning Calorimeter-The instrument2 I This test method is under the jurisdiction of ASTM Committee D-2 on Pctrolcum Products and Lubricants and is the direct responsibility of Subcom-iiiittcc 1lo2.I I on Engineering Scicnccs of High Pcrorinance Fluids and Solids.Current edition approved&i.IS.1992.Publishcd Dcccmber 1992.Originally published as D 3947-80.Last previous edition D 3947-86.2Thc DuPont Model 990 thermal analyzer with differential scanning calorimetry cell has been found satisfactory for this analysis,and is available from should have a calorimetric sensitivity of 0.05 mcal/s(0.2 mJ/s),calorimetric precision of t l%,and a temperature range from room temperature to 600C.The unit is operated in both isothermal and programmed heating modes,with the capability of holding at the final(limit)temperature.The recorder incorporates a T-axis with five range settings from 0.2 mV to 4 mV/in.and a Yaxis with sensitivities from 0.05 to 50 mcal/s.in.(0.2 to 209 mJ/s.m).5.2 Liquid Sample Pans,aluminum,with sample capacity of 0.01 mL and temperature capability up to 600C.5.3 Hermetic Press(for sealing liquid sample pans)-The press consists of a base platform and column,an adjustable lower die holder,and a movable upperdie connected to a lever arm.5.4 Analytical Balance,O.I-mg sensitivity,f 0.05-mg precision.5.5 Syringe,5OyL volume.6.Reagents and Materials 6.1 Diphenyl Ether,reagent grade,freezing range from 299 to 301 K(see Table 1).6.2 Heat Sink Material,silicone.6.3 Argon.Minimum purity with a two-stage regulator sufficient to maintain a flow rate of 25 mL/min.NOTE-:Warning Gas can reduce oxygen available for breathing.See Annex Al.1(99.997%)7.Standards 7.1 A pure material(reagent grade or higher purity)for which specific heat values have been published in the literature(for example,diphenyl ether).8.Calibration 8.1 Determine the DSC cell calibration constant,E,by running a standard material of known specific heat(for example,diphenyl ether)following the preceding procedure,9.2 to 9.7.(1)S x R x it1 60 Z PY E=where:S R=heating rate,C/min,rn=sample mass,mg,2=specific heat at the temperature of interest,=y-axis range sensitivity,and the DuPont Company;Analytical Instruments Div.:Concord Plaza-McKean Building;Wilmington,DE 19898.1 NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.ASTM D3947 92 0759530 0515160 T78 TABLE 1 Specific Heat of Diphenyl EtherA Temperature,K Specific Heat,ilmoi O K 300 218.0