فهرست مطالب j.b

This paper presents an original interactive analysis method consisting of mathematical calculation based on theoretical mechanics and mechanics of materials, and dynamics simulation for quantifying outrigger reaction forces of a kind of hydraulic mobile crane, aiming to avoid the eventualities during normal operation as far as possible, for example, tipping-over. First, a three dimensional dynamic model is established and the statically indeterminate problem of mechanics of materials is employed in the mathematical calculation. Then, the multi body dynamics simulation is investigated and the corresponding force-time curves are generated simultaneously. Finally, the validity of the proposed method is proven by comparing the amplitudes of the two kind of force-time plots upon the model. Thus, the bearing load of the crane can be limited to a feasible range for static stability or avoiding outriggers collapse.

The main purpose of this descriptive-correlational research was to study the relationship of self-efficacy and organizational commitment of faculty members to their teaching quality. The target population included 2181 faculty members of branches of Islamic Azad University in zone one. A sample of 436 respondents was selected through stratified-cluster sampling method. Research instruments included a researcher-made questionnaire of teaching quality with 27 Liker-scale statements and Cronbach’s alpha of 0. 861، Allen and Meyer’s questionnaire of organizational commitment، and Schwartzer et al. questionnaire of teachers’ self-efficacy. A use was made of multiple regression and structural equation modeling to examine the effect of exogenous factors on teaching quality. One-way ANOVA was also run to analyze the role of faculty members’ demographic variables. The results revealed that self-efficacy (with an index of 0. 42) and organizational commitment (with an index of 0. 22) had a positive، direct، and significant relationship with teaching quality. From among the dimensions of organizational commitment، emotional commitment and continuous commitment could strongly predict the variance of teaching quality. In addition، self-efficacy and organizational commitment had a significant bidirectional effect on each other. Demographic variables were found to have no significant effect on self-efficacy and organizational commitment of the faculty members.

Periodontal diseases are common in the society and some researchers suggested an association between rheumatoid arthritis (RA) and periodontal diseases. The present study was carried out to evaluate the so-called association in Iranian adults. In this case-control study, the samples were recruited from patients referred to Loghman Hospital, Tehran, during 2004-2005. Fifty patients with RA aging 27-50 with no other systemic diseases were matched for sex, age, smoking, and oral hygiene status with healthy control samples. The drugs affecting periodontium status were excluded from the study. Clinical attachment loss (CAL) index was measured by a scaled Williams periodontal probe in both groups at four surfaces, and the type of periodontitis was determined. Chi-square, Mann-Whitney U, and t-student tests served for statistical analyses. In RA group, 30 patients (60%) had moderate to severe periodontitis while in control group the condition was detected among eight patients (16%). Significant difference existed between the two groups in terms of periodontitis stage (P<0.001). Median of the CAL scores was 4.5 mm and 0 mm in RA and control patients, respectively, with significant difference (P<0.001). The results suggest higher potentiality for moderate to severe periodontitis involvement among RA patients, possibly due to similar nature of the two diseases. Periodontal assessment of RA patients is necessary for early diagnosis and consequent treatment.

Land use of Sylhet has changed gradually. This is found from the field survey that in 1970 the area was dominated by marshy land (645.33 katha), vacant land (430.88 katha) and crop land (336.17 katha). By 1988 there was no university in the area. Residential area also increased. It covered 39.11 % of total study area. Now in 2007 there is a radical change noticed in the area in comparison with 1988. Population has increased and accordingly residential area has also increased. Now it covers about 58.71 % of the study area. A survey was conducted to judge the view of the old residents of the area about the change of the land use pattern. The impacts of land use changes are desertification, climate changes and hill cutting. Improper lands use like removal of vegetal cover brings about marked changes in the local climate of Sylhet. Deforestation changes rainfall, temperature, wind speed etc. It was observed that rainfall pattern; atmospheric window of Sylhet has been changed significantly within last ten years.