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101.
Concrete precast multicell box-girder (MCB) bridges combine aesthetics with torsional stiffness perfectly. Previous analytical studies indicate that currently available specifications are unable to consider the effect of the twisting moment (torsional moment) on bridge actions. In straight bridges the effect of torsion is negligible and the transverse reinforced design is governed by other requirements. However, in the case of skewed bridges the effect of the twisting moment should be considered. Therefore, an in-depth study was performed on 90 concrete MCB bridges with skew angles ranging from 0° to 60°. For each girder the bridge actions were determined under the American Association of State Highway and Transportation Officials (AASHTO) live load conditions. The analytical results show that torsional stiffness and live load positions greatly affected the bridges?? responses. In addition, based on a statistical analysis of the obtained results, several skew correction factors are proposed to improve the precision of the simplified Henry??s method, which is widely used by bridge engineers to predict bridge actions. The relationship between the bending moment and secondary moments was also investigated and it was concluded that all secondary actions increase with an increase in skewness. 相似文献
102.
Chiong Ing Tiong Yahya Azli Mohammed Rafiq Abdul Kadir Samion Syahrullail 《浙江大学学报(A卷英文版)》2012,13(8):633-640
The effects of the mechanical factors with applied loads on the tribological performance of refined, bleached and deodorised (RBD) palm stearin (PS) were studied using a four-ball tribotester. All the RBD PS results were simultaneously compared with the additive-free paraffinic mineral oil (PMO). The experiments were carried out using different loads with a constant speed in order to gain a better understanding of the mechanical processes that occurred during the experiment. For each experiment, the temperature was increased to 75 °C and was run for 1 h. In a mechanical system, lubricant plays an important role in reducing wear and friction. PS exists as a semi-solid at room temperature after the fractionation process from oil palm. Due to the increasing rate of pollution to the environment, vegetable oil was chosen as the test lubricant with regard to its biodegradability. Other advantages of vegetable oil are that it is more easily harvestable and non-toxic compared to petroleum-based oil, which made it a suitable candidate. From the experiment, RBD PS is found to have a better friction constraint reduction compared with additive-free PMO. 相似文献
103.
There is widespread belief that exposure to television has harmful effects on children's cognitive development. Most studies that point to a negative correlation between hours of television watching and cognitive outcomes, fail to establish causality. Using the National Longitudinal Survey of Youth (NLSY) we study young children between 5 and 10 years of age during late 1990s and early 2000s. We find strong evidence of negative correlations between hours of television watched and cognitive test scores. However, once parent's characteristics and unobserved child characteristics are taken into account these correlations go away. We find that hours of television viewed per se do not have any measurable impact on children's test scores. Our results are robust to different model specifications and instrumental variable estimates. We conclude that despite the conventional wisdom and the ongoing populist movement, proactive policies to reduce children's television exposure are not likely to improve children's cognitive development and academic performance. 相似文献
104.
Sanaz Ahmadpoor Samani Siti Zaleha Abdul Rasid Saudah bt Sofian 《Performance Improvement》2015,54(9):28-35
The purpose of this article is to provide a review of background information regarding perceived level of personal control over the physical features of the work environment and its impact on individual satisfaction and outcomes. In today's business with the fast growth of technology, e‐market development, and innovative methods of communication, the workplace will continue to change rapidly. To control and accommodate these fast changes while sustaining or enhancing outcomes, organizations have increasingly turned to a model of work teams; therefore, employees’ skills in working within team environments has been emphasized. To guarantee that the work environment itself supports these new approaches of working, flexible workplaces are often suggested. Open‐plan offices offer more flexibility when compared to completely closed and private ones and they are considered to have more capabilities and are, therefore, highly valued in today's industry. Apart from its advantages, open‐plan office design does create some problems due to lack of personal control over the work environment, which can negatively affect employees’ satisfaction and performance. It is, therefore, important to emphasize the significance of personal control over the physical work environment and the impact of that on employees’ satisfaction and outcome. 相似文献
105.
Darren S. Miller Anne Michelle Parsons John Bresland Paul Herde Duc Minh Pham Angel Tan Hung-yao Hsu Clive A. Prestidge Tim Kuchel Rezaul Begg Syed Mahfuzul Aziz Ross N. Butler 《Journal of Zhejiang University. Science. B》2015,16(7):586-592
Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose 13C sodium acetate (13C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of 13CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT®L100-55 on gelatin capsules and also on DRcaps®. Test results demonstrated that DRcaps®coated with EUDRAGIT®L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine. 相似文献
106.
Deborah Rivas‐Drake Eleanor K. Seaton Carol Markstrom Stephen Quintana Moin Syed Richard M. Lee Seth J. Schwartz Adriana J. Uma?a‐Taylor Sabine French Tiffany Yip Ethnic Racial Identity in the st Century Study Group 《Child development》2014,85(1):40-57
The construction of an ethnic or racial identity is considered an important developmental milestone for youth of color. This review summarizes research on links between ethnic and racial identity (ERI) with psychosocial, academic, and health risk outcomes among ethnic minority adolescents. With notable exceptions, aspects of ERI are generally associated with adaptive outcomes. ERI are generally beneficial for African American adolescents' adjustment across all three domains, whereas the evidence is somewhat mixed for Latino and American Indian youth. There is a dearth of research for academic and health risk outcomes among Asian American and Pacific Islander adolescents. The review concludes with suggestions for future research on ERI among minority youth. 相似文献
107.
108.
The purpose of this paper is to report on who creates branding within institutions of higher learning, and what impact branding has on core institutional activities such as student recruitment and fundraising, as well as on socio‐psychological factors such as community respect and national prestige. Eighty‐nine tertiary education experts covering three world regions were surveyed in order to gather information to fulfil the paper’s objectives. The nature and extent of involvement of enrolled students, alumni, higher management, external consultants, civic leaders and the business community were investigated to identify the part each plays, if any, in the development of an institutional brand. Findings indicate that institutions have a tendency to brand from the top down rather than from the bottom up. 相似文献
109.
A.M Abdul Huq 《International Information and Library Review》2013,45(1):95-112
This paper gives a comprehensive account of the development of library and information science education in Africa. Ghana was first to start any kind of library education in 1944 but the formal education started at Ibadan, Nigeria in 1959. By 1970 there were six library schools; four new schools started during 1970s and another six during 1980s. Two Regional Schools with Master's programme in Information Science started in 1990. Two new schools are likely to start soon. Nigeria alone has eight schools providing professional education at all levels including PhD (which is only available in Nigeria) and an exclusive programme of Master in Information Science at ARCIS, Ibadan. Several schools, realizing the importance of new developments in information science and technology, are planning to incorporate this component into their curriculae. The existing programmes need to be assessed in context of information needs of Africa. 相似文献
110.