SPC and the measurement process

This paper presents the basic principles of SPC charts and how to employ SPC techniques in performing simple measurement accuracy and precision studies. Information on the concepts of variation, basic statistics, the normal distribution, and the central limit theorem are presented to set the foundation for SPC. With these concepts in place, it is possible to introduce the two SPC charts on which accuracy and precision studies can be based—individuals charts and X-bar charts. Many other types of control charts exist that are not described in this paper, specifically, control charts for attributes data. These are generally not applicable to measurement accuracy and precision studies, and numerous texts are available that sufficiently detail control charts for attributes data.     

Frequency Dependence of Fatigue Life and Internal Heating of a Fiber-Reinforced/Ceramic-Matrix Composite

The influence of loading frequency on the fatigue life and internal (frictional) heating of unidirectional SiC-fiber/ calcium aluminosilicate-matrix composites was investigated at room temperature. Specimens were subjected to tension–tension fatigue at sinusoidal loading frequencies from 25 to 350 Hz and maximum fatigue stresses of 180 to 240 MPa. The key findings of the study were that (1) fatigue life decreased sharply as the loading frequency was increased, (2) for all loading frequencies, fatigue failures occurred at stress levels that were significantly below the monotonic proportional limit stress of ∼285 MPa, and (3) pronounced internal heating occurred during fatigue, with the surface temperature of the fatigue specimens increasing by 160 K during 350-Hz fatigue at a peak stress of 240 MPa.     

News Media Use and Adolescents' Attitudes about Nuclear Issues: An American-Soviet Comparison

Both Soviet and American youth show a great concern about the possible effects of nuclear war, with heavy media users in both countries more optimistic, but the relation was stronger among Soviet students.     

Musculoskeletal status and disability of MMPI profile subgroups among patients with low back pain.

Studied Minnesota Multiphasic Personality Inventory (MMPI) profiles of 362 patients with acute and chronic low back pain (LBP) for replicable homogeneous subgroups using 3 cluster-analysis procedures. Two normal and 3 clinically elevated profile subgroups were identified. The 2 normal subgroups were characterized by relatively normal musculoskeletal condition and were least disabled but differed from each other in duration of pain, presence of physical abnormalities, and daily functioning. The most pathologic profile subgroup consisted largely of acute-pain patients whose musculoskeletal condition and daily functioning were similar to those of the normal subgroups. Patients in the 3 abnormal MMPI subgroups were exposed to more LBP physical-risk factors in the workplace. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of infrared reflectance spectroscopy to the analysis of milk and dairy products

A method for the rapid, simultaneous determination of protein, fat, carbohydrate, non-protein nitrogen and total solids in milk and liquid dairy products by infrared reflectance spectroscopy is presented. The method is calibrated against known standards obtained by conventional, time-consuming wet chemical methods but, once calibrated, can be operated routinely by non-skilled personnel. The method is sensitive and accurate down to 0·5% w/v and can be applied to most liquid samples without any need for prior preparation.     

Mechanisms of displacement discrimination with and without perceived movement.

Investigated the similarity of reference effects for different delay conditions by testing the independence of reference and delay effects in 4 experiments, using 5 young adult observers. The critical independence property was whether the spatial variables (displacement separation from the visual reference) combined independently of the temporal variable (delay). This kind of independence did not hold for displacement discrimination at delays of 50 msec and 2,000 msec. When a test for the independence property was conducted at delays of 500 msec and 4,000 msec, observers reported no perceived movement. For these longer delays, the property was satisfied. These results are discussed using the general concept of a psychophysical mechanism. Such a mechanism combines the effects of several stimulus variables into a single mediating representation. By this analysis, at least 2 mechanisms must mediate the reference effect on displacement discrimination, one for delays of 200 msec and less and another for delays of 500 msec and more. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New subscales for the MMPI-2 Social Introversion (Si) scale.

The development of three new content-homogeneous subscales for the revised Minnesota Multiphasic Personality Inventory (MMPI-2; J. N. Butcher et al, 1989) Social Introversion (Si) scale designed to replace the K. Serkownek (1975) subscales, which were not included in the revised MMPI, is described. The subscales, termed Shyness/Self-Consciousness, Social Avoidance, and Self/Other Alienation, were developed with data provided by college students (515 men and 797 women). Data analyses with this and the MMPI-2 normative sample demonstrated that the new subscales independently contribute to the assessment of nearly 90% of the variance in the full Si scale, that they display both convergent and divergent validity, and that these attributes generalize beyond the sample with which they were developed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)