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71.
72.
Kim-seng Chia Herlina Abdul Rahim Ruzairi Abdul Rahim 《Journal of Zhejiang University. Science. B》2012,13(2):145-151
Visible and near infrared spectroscopy is a non-destructive, green, and rapid technology that can be utilized to estimate
the components of interest without conditioning it, as compared with classical analytical methods. The objective of this paper
is to compare the performance of artificial neural network (ANN) (a nonlinear model) and principal component regression (PCR)
(a linear model) based on visible and shortwave near infrared (VIS-SWNIR) (400–1000 nm) spectra in the non-destructive soluble
solids content measurement of an apple. First, we used multiplicative scattering correction to pre-process the spectral data.
Second, PCR was applied to estimate the optimal number of input variables. Third, the input variables with an optimal amount
were used as the inputs of both multiple linear regression and ANN models. The initial weights and the number of hidden neurons
were adjusted to optimize the performance of ANN. Findings suggest that the predictive performance of ANN with two hidden
neurons outperforms that of PCR. 相似文献
73.
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
74.
Ilana Kaufmann Karim M. Hamza Carl-Johan Rundgren Lars Eriksson 《International Journal of Science Education》2013,35(12):1601-1624
ABSTRACTThis study explores first-year university students’ reasoning as they learn to draw Lewis structures. We also present a theoretical account of the formal procedure commonly taught for drawing these structures. Students’ discussions during problem-solving activities were video recorded and detailed analyses of the discussions were made through the use of practical epistemology analysis (PEA). Our results show that the formal procedure was central for drawing Lewis structures, but its use varied depending on situational aspects. Commonly, the use of individual steps of the formal procedure was contingent on experiences of chemical structures, and other information such as the characteristics of the problem given. The analysis revealed a number of patterns in how students constructed, checked and modified the structure in relation to the formal procedure and the situational aspects. We suggest that explicitly teaching the formal procedure as a process of constructing, checking and modifying might be helpful for students learning to draw Lewis structures. By doing so, the students may learn to check the accuracy of the generated structure not only in relation to the octet rule and formal charge, but also to other experiences that are not explicitly included in the formal procedure. 相似文献
75.
Karim Mikael Hamza Per-Olof Wickman 《International Journal of Science Education》2013,35(13):2254-2277
The purpose of this study is to use a comparative approach to scrutinize the common assumption that certain school science activities are theoretical and therefore particularly suited for engaging students with scientific ideas, whereas others are practical and, thus, not equally conducive to engagement with scientific ideas. We compared two school science activities, one (laboratory work) that is commonly regarded as focusing attention on artefacts that may distract students from central science concepts and the other (concept mapping) that is thought to make students focus directly on these concepts. We observed students in either a laboratory activity about real galvanic cells or a concept-mapping activity about idealized galvanic cells. We used a practical epistemology analysis to compare the two activities regarding students' actions towards scientific ideas and artefacts. The comparison revealed that the two activities, despite their alleged differences along the theory–practice scale, primarily resulted in similar student actions. For instance, in both activities, students interacted extensively with artefacts and, to a lesser extent, with scientific ideas. However, only occasionally did students establish any explicit continuity between artefacts and scientific ideas. The findings indicate that some of the problems commonly considered to be unique for school science practical work may indeed be a feature of school science activities more generally. 相似文献
76.
Jennifer Cutsforth Kaschak Karim Medico Letwinsky 《Clearing house (Menasha, Wis.)》2013,86(5):150-154
This study investigates the unexpected emergence of a community of practice in a middle level mathematics and science methods course. The authors describe how preservice teacher participation in a collaborative, project-based service-learning experience resulted in the formation of a community of practice characterized by teamwork, meaningful practice, and shared resources. The article concludes with a twofold argument demonstrating how collaborative, project-based service-learning experiences potentially contribute to preservice teacher learning via the positive outcomes that emerge from participation in a community of practice, while also reinforcing preservice teacher commitment to the constructive pedagogy of service-learning. 相似文献
77.
Rao AQ Hussain SS Shahzad MS Bokhari SY Raza MH Rakha A Majeed A Shahid AA Saleem Z Husnain T Riazuddin S 《Journal of Zhejiang University. Science. B》2006,7(4):291-298
Wild cotton species can contribute a valuable gene pool for agronomically desirable cultivated tetraploid cultivars. In order to exploit diploid cotton a regeneration system is required to achieve transformation based goals. The present studies aimed at optimizing the conditions for regeneration of local varieties as well as wild species of cotton. Different callus induction media were tested with varying concentrations of hormones in which sucrose was used as nutritional source. Different explants (hypocotyls, cotyledon, root) were used to check the regeneration of both local cotton plants and wild relatives using T & G medium, BAP medium, CIM medium, EMMS medium, and cell suspension medium. Different stages of embryogenicity such as early torpedo stage, late torpedo stage, heart stage, globular stage and cotyledonary stage were observed in wild relatives of cotton. The results of this study pave the way for establishing future transformation methods. 相似文献
78.
79.
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
80.
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