81,863 research outputs found
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
The Theory Of The Ideal King In “Chun Chiu Fan LU”(春秋繁露)
No full text[[abstract]]The substance of this paper is the “Theory of the King/Kingdom in Chun Chiu Fan LU(春秋繁露)”. First, I think the theory of an “ideal king” could be the problematic idea in “Chun Chiu Fan LU”. The background of the politics and the society in pre-Han dynasty, many intellects are always concerned with the morality of king and all kinds of problems in the kingdom. So, they had a great deal of discussions about king and kingdom. Chun Chiu Fan Lu continues with the political tradition; the articles in this book are written in the same way which combines the philosophical theory and king’s practice. For this reason, we can determine the problematic idea in Chun Chiu Fan LU is “ideal king”.
Then, I need to build up the theory of ideal king in Chun Chiu Fan LU. According to the articles in this writings, there are three horizons about the ideal king theory. The first is the theory of cosmology and ontology. In this horizon, we can understand the theory combines the almighty lord possessing flawless morality with the lawof air which includes Yin Yan (陰陽) and Five Elements(五行). The ideal king needs to learn the flawless morality of lord. The second is the theory about human-nature. The ideal king needs to develop his moral character through the Five Classics. The last horizon is the theory about ideal king’s moral practice. The ideal king should build up a peace and wealthy land so that the almighty lord will bless the king and kingdom. Finally, the kingdom will become a paradise where has no war and no famine.
A Note on the Ky Fan Inequality
No full textThe Ky Fan inequality is essentially the assertion that t/(1−t) is log-concave. We study its weighted form in the context of signed weights
Design of a low speed vaneaxial fan
Full text linkThe ventilation of industrial areas and tunnels is a safety requirement and
characterizes the quality of a working environment. Low speed fans are used to
achieve the required ventilation level. An attempt to design a low speed
vaneaxial fan, meeting the specifications of a given fan that is already in the
market takes place in this Thesis. The project was conducted with the support of
the Fläkt-Woods Company and the main target is to design a ventilation fan,
meeting the requirements for pressure rise, volume flow and size, of an existing
model. The efficiency improvement is driven in part by the new national and
international legislation concerning the operation of electrical equipment.
Companies require higher efficiencies without compromising safety features of
the fan and the fan capability to operate at high temperatures.
A low speed fan design procedure is established based on the available
literature and design tools. The free vortex approach is employed, which provides
acceptable efficiency and relatively simpler design. The design procedure can be
used to design a fan given a set of customer requirements. Many software tools
are used to design the fan. A Matlab code for the blade design is developed and
other codes are used to establish the final fan design. The effectiveness of the
design procedure is verified with CFD simulations carried out as part of this
project. Three new designs that are developed with the established design
procedure are presented in this Thesis. The new designs differ in the hub to tip
ratio, the rotational speed and the number of the blades and the vanes. The
experience acquired from the analysis of the performance of the first new design
is used to improve the performance of the following designs in order to achieve
the best efficiency possible. The effect of tip clearance is investigated thoroughly
in the new designs because the tip clearance has a major impact on the fan
performance and safe operation of the fan at high temperatures. The mechanical
integrity of the fan is examined last to verify that the fan can operate in high
temperature.
The target of improved efficiency (higher than 79%) is achieved in one of
the fan designs attempted and it was calculated 82%. The off design
performance of the new fan is satisfactory as well. This new design can be
further optimized, since the modification of minor design features is in itself a
methodology that can incrementally improve the efficiency of a low speed fan.
The new fan can operate at high temperatures (400°C), however the safety factor
at this temperature is 1.25 for combined steady mechanical and thermal loading
and it can be further improved either through the use of materials with better
resistance in thermal loading or with an increased tip clearance
Chun qiu Guliang zhuan zhu shu: [20 juan]. v.127
No full text范甯集解 ; 楊士勛疏.綫裝.框17.9 x 12.5 公分, 9行21字, 小字雙行同, 白口, 無魚尾, 左右雙邊, 版心下刻"汲古閣".Xian zhuang.Kuang 17.9 x 12.5 gong fen, 9 hang 21 zi, xiao zi shuang hang tong, bai kou, wu yu wei, zuo you shuang bian, ban xin xia ke "Ji gu ge".Fan Ning ji jie ; Yang Shixun shu
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