1、Designation: D2968 13Standard Test Method forMed and Kemp Fibers in Wool and Other Animal Fibers byMicroprojection1This standard is issued under the fixed designation D2968; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination by micropro-jection of the percentage of medullated fibers (med and kempf
3、ibers) in wool or other animal fibers such as mohair, cashmere,alpaca, or camels hair in their various forms.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety
4、 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD2130 Test Method for Diameter of Wool and Other AnimalFibers by MicroprojectionD4845 Terminology Relating to Wool3. Terminolo
5、gy3.1 For all terminology related to D13.13, Wool and Felt,see Terminology D4845.3.1.1 The following terms are relevant to this standard:kemp fiber, med fiber, medulla, in mammalian hair fibers,medullated fiber, wool.3.2 For definitions of all other textile terms see TerminologyD123.4. Summary of Te
6、st Method4.1 The magnified images of a specimen of the animal fibersare examined. All medullated fibers are measured and classedas either med fibers or kemp fibers. The observed numbers ofmed and kemp fibers are expressed as percentages of the totalnumber of fiber images examined.5. Significance and
7、 Use5.1 Test Method D2968 for the determination of med andkemp fibers by microprojection may be used for the acceptancetesting of commercial shipments of wool and other animalfibers, but caution is advised since only a few types of animalfibers have been subjected to interlaboratory tests to ascerta
8、inthe precision of tests for med and kemp fibers by this testmethod. Comparative tests as directed in 5.1.1 may be advis-able.5.1.1 In case of a dispute arising from differences inreported test results when using Test Method D2968 foracceptance testing of commercial shipments, the purchaser andthe s
9、upplier should conduct comparative tests to determine ifthere is a statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation ofbias. As a minimum, the two parties should take a group of testspecimens which are as homogeneous as possible and whi
10、chare from a lot of material of the type in question. The testspecimens should then be randomly assigned in equal numbersto each laboratory for testing. The average results from the twolaboratories should be compared using Students t-test forunpaired data and an acceptable probability level chosen b
11、y thetwo parties before testing is begun. If a bias is found, either itscause must be found and corrected, or the purchaser and thesupplier must agree to interpret future test results in view of theknown bias.5.2 Knowledge of the incidence of med fibers and kempfibers in wool and other animal fibers
12、 is of importance tomanufacturers of woven or knitted fabrics because of theapparent dye resistance and light reflectance qualities of thesefibers. This is not to imply that all kemp fibers will resist dyeand all med fibers will accept dye normally. In practice, aproportion of kemp fibers will appea
13、r normal after dyeing anda proportion of med fibers will appear chalky white afterdyeing. From the perspective of visual and aesthetic problems,medullated fibers having an abnormally large diameter and ahigh degree of medullation are probably the worst kind.6. Apparatus and Material6.1 The apparatus
14、 and material required in this test methodare identical to those specified in Test Method D2130.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.13 on Wool and Felt.Current edition approved July 1, 2013. Published Augus
15、t 2013. Originallyapproved in 1971. Last previous edition approved in 2008 as D2968 95 (2008).DOI: 10.1520/D2968-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to
16、the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Sampling7.1 Adequate sampling procedures for loose fibers (grease,pulled, and scoured), sliver, top, yarn, and fabric are descri
17、bedin Test Method D2130.8. Procedure8.1 Prepare the test specimens, calibrate the microprojector,condition the specimens, and prepare the slides by use of theheavy-duty cross-section device as directed in Test MethodD2130. Have two operators independently prepare at least oneslide for each test spec
18、imen.8.2 Have each of the two operators make observations usingthe procedure specified in Test Method D2130, except that onlymedullated fibers need be measured. For such fibers, measurethe diameter of both the medulla and the fiber, calculate theirratio, and classify the fiber as either med or kemp
19、as defined inand 3.1. For every fiber examined, record whether it isunmedullated, med, or kemp. See Fig. 1.8.3 Count and record the number of med and kemp fibersand the total number of animal fibers examined. Unlessotherwise directed in an applicable specification or byagreement, each operator shoul
20、d observe 500 fibers for a totalof 1000 fibers.9. Calculation9.1 Calculate, to the nearest 0.1 %, the med and kemp fiberscontent using (Eq 1) and (Eq 2):med fibers, % 5 100 m/n (1)kemp fibers, % 5 100 k/n (2)where:m = number of med fibers observed,k = number of kemp fibers observed, andn = total num
21、ber of animal fibers observed.10. Report10.1 State that the specimens were tested as directed in TestMethod D2968. Describe the material or product sampled andthe method used.10.2 Report the following information:10.2.1 The med fibers content,10.2.2 The kemp fibers content, and10.2.3 The total numbe
22、r of animal fibers observed.11. Precision and Bias11.1 Interlaboratory Test Data3An interlaboratory testwas conducted in 1970 in which three randomly drawn samplesfrom one lot of mohair top were tested in each of fivelaboratories. Two operators in each laboratory each examined500 fibers per sample.
23、The test results for med fibers and kempfibers were found to be free of bias due to sampling or testingerrors for nine of the ten operators involved.11.1.1 Interlaboratory test data are on file only for mohairtop. These test results were found to be free of bias due tosampling and testing errors for
24、 nine out of ten operators. Sincesimilar data for med and kemp measured on other types ofanimal fibers or mohair samples removed from forms otherthan top are not on file, no statements can be made concerningthe bias measurements made on such samples.11.1.2 Test results for med and kemp fibers are re
25、ported asa percent of the fibers examined. Such test results have abinomial distribution and for the small percentages of interestwould require a transformation when analyzing the data. Forthis reason, the precision of test results is evaluated in terms ofthe count of med fibers observed and the cou
26、nt of kemp fibersobserved in the 1000 fibers examined for a single test result.3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D13-1036.NOTE 1The contrast between the solid and the hollow portions of the medullated fibers is sig
27、nificantly reduced when the medulla becomes filled withmounting medium.FIG. 1 Types of Medulla in Wool and Mohair FibersD2968 132Such counts have a Poisson distribution and may be compareddirectly without requiring a transformation.11.2 Critical DifferencesTwo counts of med fibers in testresults or
28、two counts of kemp fibers in test results should beconsidered significantly different at the 95 % probability levelif the smaller of the two counts is equal to or less than the valuelisted in Table 1.NOTE 1In comparing observed counts for test results from each oftwo different laboratories, test res
29、ults from two operators within the samelaboratory, or other similar cases, Table 1 may be used, only if acomparison based on recent data obtained on specimens randomly drawnfrom one sample of the material to be evaluated has verified the absenceof bias between the two specific laboratories or operat
30、ors.11.3 Confidence LimitsSingle counts of med fibers orsingle counts of kemp fibers in a test result have the 95 %confidence limits listed in Table 2.11.4 BiasTest Method D2968 for testing the percentagesof med and kemp fibers in wool and other animal fibers has noknown bias and may be used as a re
31、feree method.12. Keywords12.1 animal fibers (except wool); microscopical examina-tion; woolTABLE 1 Values of b for Critical Differences in Number of Med orKemp Fiber Counts, a and b, for Two Test ResultsAr=a+bbr=a+bbr=a+bbr=a+bb102675118762820 7 2 930288531878240 9 4 9930503095 180603195620813170 2
32、7 28 0 33 10 58 21 83 329 1 34 10 59 21 84 3210 1 35 11 60 21 85 3211 1 36 11 61 22 86 3312 2 7 2622 73 381 3238 3414 2 9 2642 95 3 40136524 03516 3 4113662491357 4 2 46725 2 618 431 82 9339 4 56925 4 720 5 4515702695321 5 4615712696377 67227 7 823 6 481 32 9834 9 77428 925 7 50 17 75 28 100 39AThe
33、probability level for the critical difference is 95 %, for two-sided limits. If theobserved value of b 9 the tabulated value, the two test results should beconsidered significantly different at the indicated probability level.a = the larger of two counts, each of which is the total count for all spe
34、cimensin a test result, and each of which is based on the same number ofspecimens,b = the smaller of two counts taken as specified for a, andr = a+b.Where r 100, use the following:b 5 c 2 1 2 kcwhere:b = calculated value of b, rounded to the nearest whole number,c = r/ 2, andk = 1.386 for the 95 % p
35、robability level.D2968 133ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infrin
36、gement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard
37、or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views
38、known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting
39、ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 2 95 % Confidence Limits for Number o
40、f Counts per TestResultsAObservedCountLowerLimitUpperLimitObservedCountLowerLimitUpperLimit0 0.0 3.71 0.0 5.6 26 17.0 38.12 0.2 7.2 27 17.8 39.33 0.6 8.8 28 18.6 40.54 1.1 10.2 29 19.4 41.65 1.6 11.7 30 20.2 42.86 2.2 13.1 31 21.1 44.07 2.8 14.4 32 21.9 45.28 3.4 15.8 33 22.7 46.49 4.1 17.1 34 23.5
41、47.510 4.8 18.4 35 24.4 48.711 5.5 19.7 36 25.2 49.812 6.2 21.0 37 26.0 51.013 6.9 22.2 38 26.9 52.214 7.6 23.5 39 27.7 53.315 8.4 24.7 40 28.6 54.516 9.1 26.0 41 29.4 55.617 9.9 27.2 42 30.3 56.818 10.7 28.4 43 31.1 57.919 11.4 29.6 44 32.0 59.120 12.2 30.8 45 32.8 60.221 13.0 32.1 46 33.7 61.422 1
42、3.8 33.3 47 34.5 62.523 14.6 34.5 48 35.4 63.624 15.4 35.7 49 36.2 64.825 16.2 36.9 50 37.1 65.9ALower confidence limit for counts = c 1-(19 c) t (19 c)1/23Upper confidence limit for counts = d 1-(19 d)+t (19 d)1/23where:c = observed number of counts,d = c+1,andt = value of Students t for infinite degrees of freedom, two-sided limits, and thespecified probability level (t = 1.960 at the 95 % probability level).D2968 134
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