Experimental study on behaviors of polypropylene fibrous concrete beams

Synthetic fibers made from nylon or polypropylene have gained application when loose and woven into geo textile form although no information on the matrix＇s mechanical performance is obtained so that more understanding of their structural contribution to resist cracking can be determined. This paper presents the results of an experimental investigation to determine the performance characteristics of concrete reinforced with a polypropylene structural fiber. In this investigation ＂Fiber mesh＂ brand of fibers manufactured by SL Concrete System, Tennessee, USA and marketed by M/S Millennium Building System, Inc., Bangalore, India are used. The lengths of the fibers used were 24 mm. Fiber dosages used were 0.9, 1.8, 2.7 kg/m^3. A total of three mixtures, one for each fiber dosage were made. A standard slump cone test was conducted on the fresh concrete mix with and without fibers to determine the workability of the mix. The test program included the evaluation of hardened concrete properties such as compressive, split tensile, modulus of rupture and flexural strengths. The increase in compressive strength is about 36.25%, 26.20%, and 23.75% respectively that of plain concrete. This increase in strength was directly proportional to amount of fibers present in the mix. The increase in flexural strength for Mixes I-III is about 21%, 16.6%, and 23% respectively that of plain concrete specimens. An experimental investigation was also made to study the behaviors of reinforced fibers concrete beams （with longitudinal reinforcements） under two-point loading. The deflection and crack patterns were also studied. The improvements in strength and ductility characteristics were discussed.     

Factorial invariance of LibQUAL+® as a measure of library service quality over time

LibQUAL+® is an instrument purported to measure three dimensions of library service quality: service affect, library as a place, and information control. After changes were made to the instrument in 2003, however, no confirmatory factor analyses have been published in peer-reviewed journals affirming the three-factor structure of LibQUAL+®. These deficiencies were addressed by testing the hypothesized three-factor structure and the stability of that structure over time. Specifically, data from three samples (n = 550; n = 3261; n = 2103) were collected over a five-year period and analyzed using a multi-group confirmatory factor analysis. Results suggest that the theoretical model fit the data across the three samples and demonstrates factorial invariance over time. Multicollinearity between affect of service and information control, however, indicate that service quality may be measured as two dimensions rather than three, providing a more parsimonious explanation of service quality.     

Moral rationality and intuition: An exploration of relationships between the Defining Issues Test and the Moral Foundations Questionnaire

Explorations of relationships between Haidt’s Moral Foundations Questionnaire (MFQ) and indices of moral decision-making assessed by the Defining Issues Test have been limited to correlational analyses. This study used Harm, Fairness, Ingroup, Authority and Purity to predict overall moral judgment and individual Defining Issues Test-2 (DIT-2) schema scores using responses from 222 undergraduates. Relationships were not confirmed between the separate foundations and the DIT-2 indices. Using the MFQ moral judgment items only, confirmatory factor analyses confirmed higher order constructs called Individualizing and Binding foundations. Structural models using these higher order factors fitted the data well, and findings indicated that the Binding foundations significantly positively predicted Maintaining Norms and negatively predicted both overall moral judgment (N2) and the Postconventional Schema. Neither Individualizing nor Binding foundations significantly predicted Personal Interest. While moral judgments assessed by DIT-2 may not be evoking the MFQ foundations, findings here suggest the MFQ may not be a suitable measure for capturing more advanced moral functioning.     

Examining the measurement and structural invariance of LibQUAL+® across user groups

The LibQUAL+® instrument measures users' perceptions of library service quality; three factors are evaluated: Affect of Service, Information Control, and Library as Place. Although previous studies have assessed the factorial invariance of LibQUAL+®, factorial invariance by itself is insufficient for score comparability across groups. Stronger levels of measurement invariance need to be established. This study systematically tested the measurement and structural invariance of LibQUAL+® scores in a sample of 1551 undergraduate students, 707 graduate students, and 134 faculty members. Multi-group confirmatory factor analyses showed that full measurement invariance did hold between students and faculty for the complete instrument. Building on the measurement invariance, structural invariance models showed that factor variances were equivalent across user groups, but factor covariances and means differed. Faculty had higher perceptions of Affect of Service and undergraduate students had higher perceptions of Library as Place compared to the other groups.