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PubMed1958

Testing materials.

Explore the source record for details and available documents.

Hospital Administration↗
PubMed1989

Comparison of blood gas analyzer biases in measuring tonometered blood and a fluorocarbon-containing, proficiency-testing material.

This study was designed to test whether the interinstrument differences (biases) in analyses of the PO2 and PCO2 of the commercial fluorocarbon-containing emulsion (FCE) proficiency-testing material abc were similar in magnitude and direction to analyses of the PO2 and PCO2 at four similar partial pressures in tonometered blood. There were large differences among the 13 individual instrumental mean values for both blood and FCE at the four levels: for PO2 (average range, 10.3 mm Hg for blood and 17.0 mm Hg for FCE) and PCO2 (average range, 9.4 mm Hg for blood and 6.2 mm Hg for FCE). Although the instrumental biases for blood and FCE were approximately the same, the biases were slightly higher for FCE in measuring PO2 and slightly higher for blood in measuring PCO2. Accuracy and precision in blood measurement and precision in FCE measurement were significantly correlated among instruments for PO2 and PCO2. The biases of the nine instrument models evaluated significantly correlated with those of the same models participating in national surveys. We suggest that differences in technique, maintenance, and instrumental design rather than inherent differences in PO2 and PCO2 electrodes probably account for the demonstrable differences between instruments. The fluorocarbon-containing emulsion used is of value in proficiency testing for PO2 and PCO2.

Blood Gas Analysis↗
PubMed1978

Analytical and biological analyses of test materials from the synthetic fuel technologies. I. Mutagenicity of crude oils determined by the Salmonella typhimurium/microsomal activation system.

We have assayed the mutagenicity of crude industrial products and effluents with the Salmonella/microsomal activation system. Test materials (crude products from coal-conversion processes and natural crude oils) were initially fractionated into primary classes by liquid--liquid extraction and then further fractionated by column chromatography. Prescreening was accomplished over a wide concentration range with the Ames tester strains. Active fractions (mainly the neutral fractions containing polycyclic aromatic hydrocarbons and certain basic fractions) can be identified, and dose--response relationships can be established. Standard values are expressed as revertants/mg of the test material assayed with frameshift strain TA98 including metabolic activation with rat-liver preparations. Total mutagenic activity of synthetic fuel samples was consistently higher than that of natural crude "controls." Activities of subfractions are roughly additive and presumably reflect the mutagenic potential of the whole test material. These results are being extended to other genetic assays. Chemical identification is carried out along with the bioassays.

Coal↗
PubMed2005

An electromechanical material testing system for in situ electron microscopy and applications.

We report the development of a material testing system for in situ electron microscopy (EM) mechanical testing of nanostructures. The testing system consists of an actuator and a load sensor fabricated by means of surface micromachining. This previously undescribed nanoscale material testing system makes possible continuous observation of the specimen deformation and failure with subnanometer resolution, while simultaneously measuring the applied load electronically with nanonewton resolution. This achievement was made possible by the integration of electromechanical and thermomechanical components based on microelectromechanical system technology. The system capabilities are demonstrated by the in situ EM testing of free-standing polysilicon films, metallic nanowires, and carbon nanotubes. In particular, a previously undescribed real-time instrumented in situ transmission EM observation of carbon nanotubes failure under tensile load is presented here.

Journal Article↗
PubMed1997

Frictional heating of bearing materials tested in a hip joint wear simulator.

In a hip simulator wear test using bovine serum as a lubricant, the heat generated by ball-cup friction may cause precipitation of the proteins from the lubricant. The resultant accumulation of a solid layer of precipitated protein between the ball and cup could artificially protect the bearing surfaces from wear, in a manner that does not occur in vivo. Alternatively, the gradual depletion of the soluble proteins could interfere with their ability to act as boundary lubricants on the bearing surfaces, thereby artificially increasing the wear rate. Because the rate of protein precipitation may depend on the maximum temperature at the bearing surfaces during sliding, rather than the mean temperature of the bulk lubricant, this study determined the transient surface temperatures using an array of thermocouples embedded in acetabular cups of GUR 415 ultra-high molecular weight polyethylene (UHMWPE) and femoral balls of metal or ceramic, in conjunction with a finite element model of the temperature distribution. The prostheses were tested at one cycle/s under a Paul-type, physiological load profile with 2030 N maximum force, with the load cycle synchronized to the motion cycle. The steady state temperatures of the bulk lubricant were 38 degrees C for the zirconia balls, 36 degrees C for the cobalt-chromium and 33 degrees C for the alumina. However, the corresponding surface temperatures of the polyethylene, calculated with the finite element model, were 99 degrees C with zirconia ceramic, 60 degrees C with cobalt-chromium alloy, and 45 degrees C with alumina ceramic. The rank order of the surface temperatures corresponded to the relative amounts of protein that were precipitated in the test chambers during wear tests with these materials.

Animals↗
PubMed1986

The influence of temperature on the concentration homogeneity of patch test materials.

The concentration homogeneity of nickel sulphate 4.8% pet. and potassium dichromate 0.5% pet. in patch test materials appeared to become less homogeneous if stored at room temperature compared storage at 4 degrees C, after 2 months. The coefficient of variation of concentration for nickel sulphate after storage at 4 degrees C was 3.0883%, and at room temperature 25.3098%. The coefficient of variation for potassium dichromate after storage at 4 degrees C was 4.6324% and at room temperature 9.6334%. This indicates that patch test materials containing nickel sulphate and potassium dichromate should be kept refrigerated in the tropics.

Dermatitis, Contact↗
PubMed1996

Speech recognition in noise. Development of a computerized test and preparation of test material.

In adaptable, Finnish language, "speech in noise" test was developed using a personal computer equipped with a sound card. each of the 1000 test items stored as a separate digitized wave form file on the hard disk of a personal computer consisted of disyllabic words on one stereo track and synchronized speech noise on the other. Because only a few randomly selected words are presented in this test for SRTN (speech recognition threshold in noise or S/N ratio corresponding to 50% recognition) the selection and equalization of test material is considered to be crucial to the achievement of reproducible results in short time. Equalization of the test items (word + noise) in accordance with degree of difficulty, by adapting the noise signal to the properties of the corresponding word, and selection of 510 of the initial 1,000 recordings with the smallest SDs are described. The effect of this procedure on the test-retest reliability of testing SRTN is evaluated. Despite contrary expectations, the procedure appears to have no effect on the reliability of the speech recognition threshold in noise (SD from 1.5 to 1.7 dB).

Audiometry, Speech↗
PubMed1985

Material test system for the evaluation of mechanical properties of biomaterials.

A new material test system has been designed to evaluate the mechanical properties of biomaterials which are very often subject to complicated dynamic and repetitive force and deformation inside the body. The test system has high versatility, being incorporated with a miniature servo-hydraulic testing machine which can smoothly apply various modes of load and deformation to materials, and a vidicon displacement analyzer for the accurate, noncontact measurement of specimen length. A minicomputer system is used for the data acquisition and processing. Performance tests of the system and preliminary experiments on elastomeric polymers have indicated that the test system is very useful for the detailed studies of the mechanical properties of various kinds of biomaterials.

Biocompatible Materials↗
PubMed1991

Migration and material tests of some food-contact plastic wares made in Thailand.

Migration and material tests of food-contact plastic wares were carried out in compliance with the Thai Food Act. Sample materials studied were melamine resin, polyethylene, polypropylene, polystyrene, and polyvinyl chloride. Migration levels of phenol, formaldehyde, colors and heavy metals were determined. A test for vinyl chloride monomer in polyvinyl chloride was carried out. Migrant and residual levels in all samples were in compliance with the Act.

Cooking and Eating Utensils↗
PubMed2006

[Equivalence analysis of disyllabic Mandarin speech test materials].

OBJECTIVE: To evaluate the equivalence of difficulty of disyllabic Mandarin Speech Test Materials (MSTM) in order to facilitate wider use of speech audiometry in Chinese audiology clinics. METHOD: The Mandarin disyllabic materials, including 10 lists with 50 words in each, have been recorded and converted digitally into CD format. Sixty-five subjects (the age-range 18-25 years) with normal hearing who speak Mandarin well in their daily lives participated in this study. Five of them joined the pilot study, which aimed to identify a presentation level which would be used into the formal test. The other sixty subjects participated in the formal speech perception test. The results were analyzed statistically with Statistical Package for the Social Sciences Software Version 11.0 (SPSS 11.0). RESULT: Nine of the 10 lists were found to have equal difficulty with application of the ANOVA and SNK-Q statistical methods. CONCLUSION: Nine lists of 50 words of these Mandarin disyllabic materials can be considered to have equal difficulty and could be used in a clinical setting.

Adolescent↗