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11.
Bamidele V. Ayodele Maksudur R. Khan Chin Kui Cheng 《Clean Technologies and Environmental Policy》2017,19(3):795-807
This study focuses on the potential of hydrogen-rich syngas production by CO2 reforming of methane over Co/Pr2O3 catalyst. The Co/Pr2O3 catalyst was synthesized via wet-impregnation method and characterized for physicochemical properties by TGA, XRD, BET, H2-TPR, FESEM, EDX, and FTIR. The CO2 reforming of methane over the as-synthesized catalyst was studied in a tubular stainless steel fixed-bed reactor at feed ratio ranged 0.1–1.0, temperature ranged 923–1023 K, and gas hourly space velocity (GHSV) of 30,000 h?1 under atmospheric pressure condition. The catalyst activity studies showed that the increase in the reaction temperature from 923 to 1023 K and feed ratio from 0.1 to 1.0 resulted in a corresponding increase in the reactant’s conversion and the product’s yields. At 1023 K and feed ratio of 1.0, the activity of the Co/Pr2O3 catalyst climaxed with CH4 and CO2 conversions of 41.49 and 42.36 %. Moreover, the catalyst activity at 1023 K and feed ratio of 1.0 resulted in the production of H2 and CO yields of 40.7 and 40.90 %, respectively. The syngas produced was estimated to have H2:CO ratio of 0.995, making it suitable as chemical building blocks for the production of oxygenated fuel and other value-added chemicals. The used Co/Pr2O3 catalyst which was characterized by TPO, XRD, and SEM-EDX show some evidence of carbon formation and deposition on its surface. 相似文献
12.
Mei Kum Khaw Chin Hong Ooi Faisal Mohd-Yasin Anh V. Nguyen Geoffrey M. Evans Nam-Trung Nguyen 《Microfluidics and nanofluidics》2017,21(6):110
This paper reports the dynamic behaviour of a magnetically actuated floating liquid marble by analysing the oscillation of the marble. A liquid marble is a liquid droplet coated with hydrophobic powder. Magnetite particles inside the marble make it magnetic. The marble floats on a carrier liquid that contains aqueous glycerol of various concentrations. A permanent magnet located under the carrier liquid drives the floating marble with the initial velocity. Stopping the magnet abruptly causes the marble to oscillate around its final position for a few seconds. The oscillation was recorded and analysed using customised image processing and evaluation software. The damped harmonic motion model was then applied to the data and tested. Subsequently, critical parameters of the system such as the initial displacement, friction correction factor, the apparent frequency and the spring constant were determined and discussed. The simple experimental set-up and convenient theoretical approach allow us to characterise the marble motion under the influence of a magnet with good accuracy. 相似文献
13.
Lum Angeline Su Lyn Chiew Thiam Kian Ng Chirk Jenn Lee Yew Kong Lee Ping Yein Teo Chin Hai 《Universal Access in the Information Society》2017,16(3):775-791
Universal Access in the Information Society - In recent years, researchers have attempted to shift patient decision aids (PDAs) from paper-based to web-based to increase its accessibility. Insulin... 相似文献
14.
A common computer-based collaborative learning approach is to simply introduce contemporary computermediated communication technology into the classroom to support prescribed learning activities. This approach assumes that all students collaborate in similar ways and that presentday technology is sufficient to accommodate all collaboration forms. This view is superficial and limiting. Students collaborate in different ways at different levels on different learning activities. A more detailed articulation of collaboration in learning is crucial to understanding and extending the pedagogical capabilities and usefulness of collaborative technologies. A model is presented for a more finely articulated form of analysis that enumerates types of collaborative learning activities and evaluates how these activities may be supported through different design options. The analysis is based on actual classroom scenarios and the collaboration requirements that emerge from them. The authors have successfully applied this analysis model in the design of a computer-based collaborative learning environment for science education. 相似文献
15.
Previous studies on business simulation games (BSGs) have concluded that improved performance may not be the primary benefit of using BSGs, due to mixed results between student performance and perceptions. Two relevant and insightful issues attract our attention, namely, the impacts of the heterogeneous student population and the different complexity levels of BSG software. To address these issues, the present study aims to understand the relationship between student profile/characteristics and performance in the classroom with BSG-facilitated learning. An in-depth case study is conducted on a general college course designed to teach three different complexities of BSGs to students enrolled in different majors. Four student profile factors are individually tested for differences in performance scores as evaluated by the teacher. Additionally, the influences of 11 student characteristics are assessed with regard their self-reported perceived learning performances. Regression analysis and ANOVA are used to investigate the impacts of heterogeneous users and game complexity on student performance. Based on the regression analyses of the data collected from 43 respondents who participated in the general course, the study concludes that knowledge and skill may influence the heterogeneous student population; moreover, student participation and tacit learning preference improve performance, and students with an auditory learning preference or high learning motivation may not perform well in classroom BSG learning. However, the low value of adjusted R square implies that more dimensions or variables are needed to increase the explaining power of the performance scores in the regression analyses. In contrast, heterogeneous BSG software with different complexity levels present different results. The current research contributes practical and incremental knowledge on the complexity of heterogeneous BSG software on performance scores and the perceived learning performance of heterogeneous student populations. With the research limitations acknowledged, a series of suggestions for teachers pertaining to appropriate applications of BSGs in classes is offered as well as recommendations to BSG providers. Nevertheless, in-depth analyses are required, preferably with larger student population samples, to further explore the insignificant relationship between student perceptions and attitude under nonlinear extended complexity. 相似文献
16.
Calculating the elastic moduli of steel-fiber reinforced concrete using a dedicated empirical formula 总被引:1,自引:0,他引:1
The equivalent inclusion method (EIM) is adopted to study the characteristics of the equivalent material properties of steel-fiber reinforced concrete as a function of the volume fraction and the length to diameter ratio of the fibers. It is found that the equivalent material moduli of concrete reinforce with randomly orientated and distributed fibers are insensitive to the length to diameter ratio of the steel fibers. A set of empirical formulae is then proposed for the purposes of engineering applications. The proposed empirical model can simplify the calculation of the equivalent material moduli. Verifications of the proposed empirical formulae with the EIM model and with experimental data are performed with two examples. The first is a compression test. The second is 4 point bending test. The empirical formulae, based on the equivalent inclusion method proposed in this study, represent an alternative means of quickly calculating the effective elastic modulus of steel-fiber reinforced concrete materials. 相似文献
17.
In this paper, a complete dynamic model on task space for a 6 degrees of freedom (DOF) Gough‐Stewart platform‐type computer numerical control (CNC) machine is derived. The rotation terms of the legs are included for those inertia effects cannot be negligible in the machine tool applications. The formulation derived by means of the Euler‐Lagrange method is convenient for designing the adaptive control law. Also, the average‐type force model for end milling process is derived and included in the dynamic model and control. A composite adaptive control scheme is developed by use of filtering dynamics technique. An appropriate estimator gain is designed in the parameter adaptation law that is useful for estimating the selected important cutting parameters. Experimental results verify the proposed adaptive control scheme can achieve good tracking performance. © 2004 Wiley Periodicals, Inc. 相似文献
18.
Kwai-Sang Chin Lian-Yu Zheng Li Wei 《The International Journal of Advanced Manufacturing Technology》2003,22(9-10):733-743
This paper proposes a hybrid approach to develop a rough-cut process planning for quality. The approach aims to determine key process alternatives with an adequate process capability by systematic quality planning and assessment methods during the initial planning stage of the product development cycle. It consists of four steps: (1) identification of quality characteristics (2) planning of the process quality by combining quality function deployment (QFD) with the process failure mode and effect analysis (FMEA) (3) a selection of process alternatives, and (4) an assessment of process quality through a quality measure index, called the composite process capability (CCP). The process alternatives with an adequate CCP selected during the early design stage can then be not only used as the guidelines for detailed process planning but also as feedback for the product design and other functions for design evaluation and improvement. This approach is helpful to reduce or even eliminate the iterations of modification of process plans. A prototype system called the rough-cut process planning for quality (RPPFQ) has been developed for validation. A case study concerned with a satellite frame part is presented to illustrate the approach and prototype system in this paper. 相似文献
19.
The first official shift in communication systems from fixed-location devices to portable/mobile devices happened in 1973 when Martin Cooper, general manager of Motorola's Communications Systems Division at the time, placed the first mobile call from a New York street using AT&T's network. Four years later, the first cell phone was made in Chicago with free trials offered to more than 2,000 people. The first commercial handset to receive FCC approval was Motorola's DynaTAC in 1983 [1], which was made available to the public a year later. This 1.13 kg (2.5 lb) phone that cost consumers US$3,500 was only able to achieve approximately 35 minutes of talk time and took almost 15 years to develop with the cost totaling US$100 million. 相似文献
20.
Silvia Nappini Danil W. Boukhvalov Gianluca D'Olimpio Libo Zhang Barun Ghosh Chia‐Nung Kuo Haoshan Zhu Jia Cheng Michele Nardone Luca Ottaviano Debashis Mondal Raju Edla Jun Fuji Chin Shan Lue Ivana Vobornik Jory A. Yarmoff Amit Agarwal Lin Wang Lixue Zhang Federica Bondino Antonio Politano 《Advanced functional materials》2020,30(22)
By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) transition‐metal dichalcogenide in catalysis and nanoelectronics is assessed. The Te surface termination forms a TeO2 skin in an oxygen environment. In ambient atmosphere, passivation is achieved in less than 30 min with the TeO2 skin having a thickness of about 7 Å. NiTe2 shows outstanding tolerance to CO exposure and stability in water environment, with subsequent good performance in both hydrogen and oxygen evolution reactions. NiTe2‐based devices consistently demonstrate superb ambient stability over a timescale as long as one month. Specifically, NiTe2 has been implemented in a device that exhibits both superior performance and environmental stability at frequencies above 40 GHz, with possible applications as a receiver beyond the cutoff frequency of a nanotransistor. 相似文献