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51.
Milivoj K. Burn 《Journal of the American Ceramic Society》1992,75(7):1914-1917
An apparatus for measurement of the fiber/matrix interfacial shear stress at temperatures up to 1100° is described. Equipment was used to measure interfacial properties as a function of temperature in two ceramic-matrix composites and one metal-matrix composite. In the composites where the thermal expansion of the matrix was higher than that of the fiber, the interfacial shear stress decreased with temperature. The opposite trend was observed in a system with low matrix thermal expansion. The change of the interfacial shear stress with temperature of all the composites studied can be fully explained by considering the fiber/matrix expansion differences. 相似文献
52.
Santosh K. Verma Zhe Zhao Theodore K. Courtney Wen-Ruey Chang David A. Lombardi Yueng-Hsiang Huang 《Ergonomics》2014,57(12):1919-1926
Several studies have indicated that slip-resistant shoes may have a positive effect on reducing the risk of slips and falls, a leading cause of injury at work. Few studies, however, have examined how duration of shoe usage affects their slip-resistance properties. This study examined the association between the duration of slip-resistant shoes usage and the self-reported rate of slipping in limited-service restaurant workers. A total of 475 workers from 36 limited-service restaurants in the USA were recruited to participate in a 12-week prospective study of workplace slipping. Of the 475 participants, 83 reported changing to a new pair of shoes at least once during the 12-week follow-up. The results show that slip-resistant shoes worn for less than six months were moderately more effective than those worn for more than six months. Changing to a new pair of shoes among those wearing slip-resistant shoes at baseline was associated with a 55% reduction in the rate of slipping (RR = 0.45, 95% CI = 0.23–0.89). Further research is needed to develop criteria for the replacement of slip-resistant shoes.
Practitioner Summary: The duration of usage impacts the slip-resistance properties of slip-resistant shoes. Slip-resistant shoes worn for less than six months were moderately more effective in reducing slips than slip-resistant shoes worn for more than six months. Shoe use policies should not only encourage or require their use but also include guidance on replacing slip-resistant shoes at regular intervals. 相似文献
53.
Kaiyu Zhao Matthew O. Ward Elke A. Rundensteiner Huong N. Higgins 《Computer Graphics Forum》2014,33(3):331-340
Linear models are commonly used to identify trends in data. While it is an easy task to build linear models using pre‐selected variables, it is challenging to select the best variables from a large number of alternatives. Most metrics for selecting variables are global in nature, and thus not useful for identifying local patterns. In this work, we present an integrated framework with visual representations that allows the user to incrementally build and verify models in three model spaces that support local pattern discovery and summarization: model complementarity, model diversity, and model representivity. Visual representations are designed and implemented for each of the model spaces. Our visualizations enable the discovery of complementary variables, i.e., those that perform well in modeling different subsets of data points. They also support the isolation of local models based on a diversity measure. Furthermore, the system integrates a hierarchical representation to identify the outlier local trends and the local trends that share similar directions in the model space. A case study on financial risk analysis is discussed, followed by a user study. 相似文献
54.
There is increasing evidence that user characteristics can have a significant impact on visualization effectiveness, suggesting that visualizations could be designed to better fit each user's specific needs. Most studies to date, however, have looked at static visualizations. Studies considering interactive visualizations have only looked at a limited number of user characteristics, and consider either low‐level tasks (e.g., value retrieval), or high‐level tasks (in particular: discovery), but not both. This paper contributes to this line of work by looking at the impact of a large set of user characteristics on user performance with interactive visualizations, for both low and high‐level tasks. We focus on interactive visualizations that support decision making, exemplified by a visualization known as Value Charts. We include in the study two versions of ValueCharts that differ in terms of layout, to ascertain whether layout mediates the impact of individual differences and could be considered as a form of personalization. Our key findings are that (i) performance with low and high‐level tasks is affected by different user characteristics, and (ii) users with low visual working memory perform better with a horizontal layout. We discuss how these findings can inform the provision of personalized support to visualization processing. 相似文献
55.
S. Chaturvedi C. Dunne Z. Ashktorab R. Zachariah B. Shneiderman 《Computer Graphics Forum》2014,33(8):52-68
An important part of network analysis is understanding community structures like topological clusters and attribute‐based groups. Standard approaches for showing communities using colour, shape, rectangular bounding boxes, convex hulls or force‐directed layout algorithms remain valuable, however our Group‐in‐a‐Box meta‐layouts add a fresh strategy for presenting community membership, internal structure and inter‐cluster relationships. This paper extends the basic Group‐in‐a‐Box meta‐layout, which uses a Treemap substrate of rectangular regions whose size is proportional to community size. When there are numerous inter‐community relationships, the proposed extensions help users view them more clearly: (1) the Croissant–Doughnut meta‐layout applies empirically determined rules for box arrangement to improve space utilization while still showing inter‐community relationships, and (2) the Force‐Directed layout arranges community boxes based on their aggregate ties at the cost of additional space. Our free and open source reference implementation in NodeXL includes heuristics to choose what we have found to be the preferable Group‐in‐a‐Box meta‐layout to show networks with varying numbers or sizes of communities. Case study examples, a pilot comparative user preference study (nine participants), and a readability measure‐based evaluation of 309 Twitter networks demonstrate the utility of the proposed meta‐layouts. 相似文献
56.
57.
《International journal of human-computer studies》2014,72(1):126-139
Emergency planning is an ongoing activity in which a multidisciplinary group of experts intermittently collaborate to define the most appropriate response to risks. One of the most important tasks of emergency planning is the review of plans as a way of maintaining, refining, and improving them. This review of plans is based on exchanging knowledge and experiences in order to take into account different perspectives and generate alternative solutions. An exploratory case study carried out within municipal organizations has disclosed how the application of rigid plan reviewing practices hinders team creativity and, consequently, effective decision-making. This paper presents a computer-based collaborative environment aimed at supporting unstructured team discussion during the post-hoc review of emergency plan. This collaborative environment allows emergency planning team members to share their view in a free manner by interacting with user interface components distributed across several input and output dimensions. The usage of the environment has proved how the application of new interactive technologies can create more dynamic work settings, fostering team creativity. 相似文献
58.
Continuous α-Fe2 O3 films grown on bulk (0001)Al2 O2 substrates by low-pressure chemical vapor deposition have been studied by transmission electron microscopy and the observations compared to those obtained from discontinuous films at an earlier stage of the growth process. Plan-view specimens revealed significant thermal stress in the continuous films, while cross-sectional specimens showed that cracking occurs in thicker films. The free surface of the film and the film/substrate interface appeared sharp and flat, apart from growth ledges and steps. Weak-beam imaging revealed a hexagonal misfit dislocation network consisting of perfect edge dislocations. Fine structure in the selected-area diffraction patterns which corroborates these observations is also discussed. The misfit network of partial dislocations previously observed in the discontinuous films was not observed for the continuous films, indicating an effect of film thickness, growth rate, or surface preparation on the Fe2 O3 /(0001)Al2 O3 interface structure. 相似文献
59.
The coupling efficiency of seven coupling agents in wood–polymer composites (WPC) was investigated in this study. The improvement on the interfacial bonding strength, flexural modulus, and other mechanical properties of the resultant wood fiber/high‐density polyethylene (HDPE) composites was mainly related to the coupling agent type, function groups, molecular weight, concentration, and chain structure. As a coupling agent, maleated polyethylene (MAPE) had a better performance in WPC than oxidized polyethylene (OPE) and pure polyethylene (PPE) because of its stronger interfacial bonding. A combination of the acid number, molecular weight, and concentration of coupling agents had a significant effect on the interfacial bonding in WPC. The coupling agents with a high molecular weight, moderate acid number, and low concentration level were preferred to improve interfacial adhesion in WPC. The backbone structure of coupling agents also affected the interfacial bonding strength. Compared with the untreated composites, modified composites improved the interfacial bonding strength by 140% on maximum and the flexural storage modulus by 29%. According to the statistical analysis, 226D and 100D were the best of the seven coupling agents. The coupling agent performance was illustrated with the brush, switch, and amorphous structures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 93–102, 2005 相似文献
60.
Unique explanations are given to describe changes in the mixing torque and tensile and impact properties of poly(vinyl chloride) (PVC)/wood sawdust composites affected by various types and concentrations of silane coupling agents. Concentrations of 0.5–1.0 and 1.5 wt % coupling agent are recommended for the optimization of the tensile and impact properties of the composites, respectively. Changes in the tensile and impact properties of the composites with a low sawdust content were more sensitive to the addition of silane coupling agents than those with a high sawdust content. KBM603 was suitable for improving the tensile properties, whereas KBE603 is recommended for high impact resistance of the composites. The differences in the mechanical and thermal properties of the PVC/sawdust composites were dependent on the characteristics of the functional groups in the silane coupling agents used, such as hydrophilic level, number of functional groups, self‐condensation reaction, and effectiveness of the hydrolysis reaction. Silane coupling agents above 1.0 wt % resulted in an increase in polyene sequences in the PVC structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 213–221, 2005 相似文献