Matching Items (2)

Filtering by

Clear all filters

153035-Thumbnail Image.png

Reconciling the differences between tolerance specification and measurement methods

Description

Dimensional Metrology is the branch of science that determines length, angular, and geometric relationships within manufactured parts and compares them with required tolerances. The measurements can be made using either manual methods or sampled coordinate metrology (Coordinate measuring machines). Manual

Dimensional Metrology is the branch of science that determines length, angular, and geometric relationships within manufactured parts and compares them with required tolerances. The measurements can be made using either manual methods or sampled coordinate metrology (Coordinate measuring machines). Manual measurement methods have been in practice for a long time and are well accepted in the industry, but are slow for the present day manufacturing. On the other hand CMMs are relatively fast, but these methods are not well established yet. The major problem that needs to be addressed is the type of feature fitting algorithm used for evaluating tolerances. In a CMM the use of different feature fitting algorithms on a feature gives different values, and there is no standard that describes the type of feature fitting algorithm to be used for a specific tolerance. Our research is focused on identifying the feature fitting algorithm that is best used for each type of tolerance. Each algorithm is identified as the one to best represent the interpretation of geometric control as defined by the ASME Y14.5 standard and on the manual methods used for the measurement of a specific tolerance type. Using these algorithms normative procedures for CMMs are proposed for verifying tolerances. The proposed normative procedures are implemented as software. Then the procedures are verified by comparing the results from software with that of manual measurements.

To aid this research a library of feature fitting algorithms is developed in parallel. The library consists of least squares, Chebyshev and one sided fits applied on the features of line, plane, circle and cylinder. The proposed normative procedures are useful for evaluating tolerances in CMMs. The results evaluated will be in accordance to the standard. The ambiguity in choosing the algorithms is prevented. The software developed can be used in quality control for inspection purposes.

Contributors

Agent

Created

Date Created
2014

157636-Thumbnail Image.png

Situational Shyness among Chinese Adolescents: Measurement and Associations with Adjustment

Description

Although researchers often conceptualize shyness as stable across different situations (e.g., Rubin, Coplan, & Bowker, 2009), evidence has suggested that shyness may consist of situation-specific components (e.g., Asendorpf, 1990a; 1990b; Gazelle & Faldowski, 2014; Xu & Farver, 2009). This study

Although researchers often conceptualize shyness as stable across different situations (e.g., Rubin, Coplan, & Bowker, 2009), evidence has suggested that shyness may consist of situation-specific components (e.g., Asendorpf, 1990a; 1990b; Gazelle & Faldowski, 2014; Xu & Farver, 2009). This study was aimed at developing a systematic measurement tool for situational shyness in adolescence, as well as examining the relations between situational shyness and other popular measures of shyness and between situational shyness and adjustment. A sample of Chinese adolescents (N = 492) from an urban school participated in the study during 7th (T1) and 8th (T2) grades. Adolescents self-reported their situational shyness using a new measure of hypothetical scenarios, as well as their general shyness, anxious shyness, regulated shyness, depressive symptoms, and loneliness. Peers reported adolescents’ general and conflicted shyness, and popularity and peer rejection. The school provided records of their academic achievement (exam scores).

Exploratory and confirmatory factor analyses of the situational shyness measure consistently supported that shyness in the hypothetical scenarios can be separated into three components: shyness with familiar peers, shyness with unfamiliar peers, and shyness in formal situations. These components had differential associations with other measures of shyness. Self-reported general and anxious shyness were related consistently to shyness with unfamiliar peers and in formal situations, and occasionally to shyness with familiar peers. Self-reported regulated shyness was not related to self-reported shyness in any situation. Peer-reported conflicted shyness was associated with shyness with familiar and unfamiliar peers, whereas peer-reported general shyness was associated with shyness with unfamiliar peers and in formal situations. Moreover, situational shyness showed differential relations to maladjustment. Shyness with familiar peers was associated positively with maladjustment in multiple domains, especially academic and peer difficulties. Shyness with unfamiliar peers and shyness in formal situations, in contrast, were associated primarily with internalizing problems. In addition, shyness with unfamiliar peers and in formal situations occasionally related to positive adjustment, suggesting shyness in specific situations may still be protective in contemporary urban China. The findings provided new evidence that the correlates of shyness depend on the situation in which shyness occurs, and may inform future intervention programs.

Contributors

Agent

Created

Date Created
2019