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排序方式: 共有428条查询结果,搜索用时 15 毫秒
21.
This paper describes the results of three case studies in which the subcontractor-fabricator relations had a significant negative effect on labor productivity of the subcontractor. Late vendor deliveries, fabrication or construction errors, and out-of-sequence deliveries plagued each of the three projects. On two projects, there were work stoppages because there were no materials. Unsequenced deliveries caused unnecessary crane movements and rework. On the third project, the output of the fabrication shop was not compatible with the output of the erection crew. The baseline productivity was calculated, and the loss of labor efficiency in each case was estimated to be 16.6, 28.4, and 56.8%. These percentages were compared with similar percentages calculated from other published articles that described inefficient site storage conditions and delivery methods. The labor inefficiencies caused by material management range from a low of 5.4% to a high of 56.8%. The schedule slippage on the three case study projects was estimated to be between 50 and 129%. 相似文献
22.
23.
Gary B. Randolph 《工程教育杂志》2000,89(2):119-122
The principles of “Writing Across the Curriculum” (WAC) has the potential to help educators more fully engage the learning styles of all students and achieve higher levels of learning according to the Bloom taxonomy. WAC exercises were built into an information systems class to create a fully collaborative learning approach. Students worked as a team on in‐class exercises, edited each other's work, and even collaborated on examinations. Students indicated that they learned more in this format. They also said that even examinations were learning experiences, incorporating brainstorming and discussion. 相似文献
24.
Ned Randolph 《电器评介》2007,(12)
美国Walt Disney公司旗下的ABC系列热门电视剧《疯狂主妇》(Desperate Housewives)、《实习医生格雷》(Grey's Anatomy)和《迷失》(Lost)的DVD光盘发行销售额使该公司2007年第四财季的净收入飙升了12%. 相似文献
25.
Burack Jacob A.; Enns James T.; Iarocci Grace; Randolph Beth 《Canadian Metallurgical Quarterly》2000,36(6):731
Visual search for compound patterns was examined in observers aged 6, 8, 10, and 22 years. The main question was whether age-related improvement in search rate (response time slope over number of items) was different for patterns defined by short- versus long-range spatial relations. Perceptual access to each type of relation was varied by using elements of same contrast (easy to access) or mixed contrast (hard to access). The results showed large improvements with age in search rate for long-range targets; search rate for short-range targets was fairly constant across age. This pattern held regardless of whether perceptual access to a target was easy or hard, supporting the hypothesis that different processes are involved in perceptual grouping at these two levels. The results also point to important links between ontogenic and microgenic change in perception (H. Werner, 1948, 1957). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
Hugo E. Acosta-Martinez Susan M. Gourvenec Mark F. Randolph 《Soils and Foundations》2008,48(2):247-254
Shallowly embedded skirted foundations are an attractive alternative to piles for jacket structures and buoyant facilities as they can resist uplift but are cheaper to install than deep foundations. Bearing capacity of shallow skirted foundations in compression is moderately well understood while there is still considerable uncertainty over uplift capacity, particularly for loading sustained over a period of time. This paper reports results from beam centrifuge tests on a shallow skirted foundation in clay, subjected to uplift and compression. Rapid and sustained loading is considered and the effects of consolidation stress level and stress history on undrained capacity and sustained load response are reported. 相似文献
27.
The present trend in research on psychological stress is to examine the appraisal process for explanations of the wide individual differences typically found in responses to identical stressors. This approach comes at the expense of attempts to determine how aspects of the stimulus configuration tend to influence response independent of individual differences. The latter technique is unable to explain much of the variability in response, but it does avoid the circularity that regularly confronts the appraisal-based approach. In this article we describe the situational determinants of the primary appraisal of threat in a specific and systematic manner. Each potential determinant is broken down and the relevant empirical and theoretical literature is reviewed. Eight propositions about the workings of these factors are presented and discussed. Primary attention is given to the factors of event severity, imminence, and probability of occurrence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
The partition of free fatty acids (FFA) to egg-phosphatidylcholine (egg-PC) and egg-phosphatidylethanolamine (egg-PE) vesicles was studied. Upon the addition of FFA to the suspension of vesicles, the pH of the aqueous phase changed depending on the length and saturation of the FFA hydrocarbon chain, as well as on the vesicle composition. The medium pH decreased faster if FFA was added to egg-PE as compared to egg-PC vesicles. The fluorescent free fatty acid indicator (ADIFAB) was used to measure the amount of FFA remaining in the aqueous phase. Most of the FFA added to the suspension of egg-PE vesicles remained in the aqueous phase, whereas in the presence of egg-PC vesicles the FFA partitioned preferentially into the lipid phase. The amount of FFA incorporated into the lipid bilayers was estimated by measuring the changes of pH at the lipid bilayer surface, using fluorescein-PE. At high surface concentrations of FFA, decreasing pH at the bilayer surface caused the protonation of FFA, and raised the pK of FFA at the bilayer surface from 5 to about 7. The partition of FFA in egg-PE vesicles was an order of magnitude lower than that in egg-PC vesicles. The incorporation amount was determined more by the molecular packing than by the nature of lipid headgroups, because steroylcaprioyl-PE, which preferred the bilayer structure, behaved more like egg-PC than egg-PE. Understanding FFA partition characteristics would help to interpret the hydrolysis measurements of phospholipids, and to explain many biological activities of FFA. 相似文献
29.
Jianguo Zhang Douglas P. Stewart Mark F. Randolph 《Canadian Metallurgical Quarterly》2002,128(5):363-371
The results of centrifuge modeling of pipe–soil interaction for shallowly embedded offshore pipelines are presented. A non-associated bounding surface model is constructed in vertical–horizontal (V–H) load space on the basis of test data and the theory of plasticity to simulate the response of a pipeline embedded in sandy soil under combined (vertical and horizontal) monotonic loading, taking into account possible pre-loading effects. The model needs nine parameters that can be back calculated from model or field tests and in some cases estimated theoretically. It provides a suitable basis for modeling the load-displacement response of shallowly embedded offshore pipelines. The model reproduces the key features of the load-displacement response of pipelines observed in centrifuge model tests. In particular, the adoption of bounding surface plasticity allows a gradual transition from elastic to plastic response to be simulated and the introduction of a non-associated flow rule allows the model to predict the strain-softening behavior of pipes under horizontal loading. The lateral breakout resistance predicted by the model agrees very well with experimental data. 相似文献
30.
Adult male red-sided garter snakes (Thamnophis sirtalis parietalis) received radio-frequency lesions prior to 17 weeks of low-temperature hibernation. Animals found to have bilateral lesions of the anterior hypothalamus-preoptic area ({ah-poa}) failed to exhibit courtship behavior on emergence from hibernation. Those individuals in which the major portion of the destruction was centered in the anterior POA also exhibited deficits in thermoregulatory behavior. Animals that received unilateral lesions of the {ah-poa} initiated courtship behavior after controls and had an abbreviated period of courtship; these animals exhibited normal responses to thermal stimuli. Male snakes with lesions outside the {ah-poa} courted normally and demonstrated no differences in thermoregulatory behavior compared with the surgical controls. These results indicate that in male red-sided garter snakes, an intact {ah-poa} is critical for the integration of thermal stimuli that activate seasonal courtship behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献