Preparation and evaluation of sol-gel made nickel catalysts for carbon dioxide reforming of methane

Sol-gel (solution-gelation) method was used to prepare Ni-Ti and Ni-Ti-Al catalysts for reforming of methane with carbon dioxide. This method, after optimizing the parameters such as hydrolysis and acid/alkoxide ratio, is able to make a Ni-Ti catalyst with a surface area as high as 426m2/g when calcined at 473K; but calcination at higher temperature lead to dramatic decrease in surface area. XRD, XPS, TEM and SEM were used to understand this change. Using a packed bed reactor, the catalysts were evaluated with the reforming reaction. It was found that the activity of the Ni-Ti catalyst increases with the Ni loading in the range of 1-10wt%. The reduction temperature has strong effect on activity of the reduced catalyst. Up to 973K, the activity increases with the reduction temperature; but after 973K, the activity decreases and become 0 when the temperature is over 1023K. The Ni-Ti catalyst also deactivated as 15% after 4h of time on stream. The XRD analysis shows that Ti3O5 formed in the catalyst after higher-temperature reduction as well as after the reaction for a period of time. The formation of Ti3O5 may render the catalyst to loss its activity. However, further study is expected to understand the mechanism. TG/DTA analysis shows that both Ni-Ti and Ni-Ti-Al catalysts had carbon deposition; but the latter maintained higher activity in a longer period of time

Introducing critical elements of cross-cultural scholarship development: A discussion towards a model

Theorizing existing literature, we present a model outlining five essential elements to guide cross-cultural scholarship practices. A scenario showcases how to apply these elements to practical situations

Examining The Impact of a DSP Project Through a Comparative Adult Education Lens: A Snapshot of Principal Professional Development for Education Internationalization in Beijing, China

Through the lenses of comparative adult education and international educational leadership development, this study explores the learning experiences of local school principals after they participated in a professional development program named Domestic Study Program (DSP) in Beijing. A qualitative narrative inquiry was applied and four school principals who self-reported as experiencing personal and professional improvement through the DSP program were interviewed. Their lived learning experiences as adult learners through the DSP project were sorted, categorized, grouped, and regrouped following the qualitative research data analysis protocols suggested by Rossman and Rallis (2003) and Creswell (2014). The research indicates that the four local principals experienced major changes in the areas of self-perception, ways of thinking, and ways of doing. The findings are interpreted through the lenses of comparative adult education and international educational leadership development

An adaptive shortest-solution guided decimation approach to sparse high-dimensional linear regression

High-dimensional linear regression model is the most popular statistical model for high-dimensional data, but it is quite a challenging task to achieve a sparse set of regression coefficients. In this paper, we propose a simple heuristic algorithm to construct sparse high-dimensional linear regression models, which is adapted from the shortest solution-guided decimation algorithm and is referred to as ASSD. This algorithm constructs the support of regression coefficients under the guidance of the least-squares solution of the recursively decimated linear equations, and it applies an early-stopping criterion and a second-stage thresholding procedure to refine this support. Our extensive numerical results demonstrate that ASSD outperforms LASSO, vector approximate message passing, and two other representative greedy algorithms in solution accuracy and robustness. ASSD is especially suitable for linear regression problems with highly correlated measurement matrices encountered in real-world applications.Comment: 13 pages, 6 figure

Tail dependence for heavy-tailed scale mixtures of multivariate distributions

Abstract The tail dependence of multivariate distributions is frequently studied via the tool of copulas. This paper develops a general method to evaluate the tail dependence of heavy-tailed scale mixtures of multivariate distributions whose copulas are not explicitly accessible. The tractable formulas of tail dependence indexes are derived and the monotonicity properties of these indexes with respect to the distribution parameters are established. The multivariate elliptical distribution and multivariate Pareto distribution are discussed to illustrate the results

Guest editorial: Adult and higher education in changing global contexts: innovative theory and practices from Asian countries and beyond

© 2023, Emerald Publishing Limited. This AAM is provided for your own personal use only. It may not be used for resale, reprinting, systematic distribution, emailing, or for any other commercial purpose without the permission of the publisher.We are delighted to present this Special Issue (SI) entitled Adult and Higher Education in Changing Global Contexts: Innovative Theory and Practices from Asian Countries and Beyond to the esteemed readers of the Journal of Higher Education, Skills, and Work-Based Learning (HESWBL). The inspiration behind this issue stems from over two decades of research and scholarship presented at the Asian Adult Education Conference (AAE) (https://asianadulteducation.weebly.com/) originally known as the Asian Diaspora Adult Education Pre-Conference that has been organized in conjunction with the Adult Education Research Conference (AERC). AAE's mission has been to provide an academic forum for research and scholarship exchange, and mutual collaborations among scholars, researchers, educators, practitioners and policymakers in adult and higher education from the East, West and Rest. Since 2003, AAE has grown into the leading pre-conference at AERC, actively promoting research and co-constructing academic scholarship in the adult and higher education field

A Novel High Linearity and Low Power Folded CMOS LNA for UWB Receivers

© 2017 World Scientific Publishing Company. Electronic version of an article published as Journal of Circuits, Systems and Computers, Vol. 27, No. 03, 1850047, https://doi.org/10.1142/S0218126618500470.This paper presents a high linearity and low power Low-Noise Amplifier (LNA) for Ultra-Wideband (UWB) receivers based on CHRT 0.18μm CMOS technology. In this work, the folded topology is adopted in order to reduce the supply voltage and power consumption. Moreover, a band-pass LC filter is embedded in the folded-cascode circuit to extend bandwidth. The transconductance nonlinearity has a great impact on the whole LNA linearity performance under a low supply voltage. A post-distortion (PD) technique employing an auxiliary transistor is applied in the transconductance stage to improve the linearity. The post-layout simulation results indicate that the proposed LNA achieves a maximum power gain of 12.8dB. The input and output reflection coefficients both are lower than -10.0dB over 2.5~11.5GHz. The input third-order intercept point (IIP3) is 5.6dBm at 8GHz and the noise figure (NF) is lower than 4.0dB. The LNA consumes 5.4mW power under a 1V supply voltage.Peer reviewe

Synthesis and Application of Dendriticlinear Polymer PAMAM-Si for Leather Fatliquoring Process

Content: Environmental pollution caused by leather making is the primary concern in the development of leather industry. The use of safe, effective and multi-functional green chemical products has the advantages of reducing leather operations, increasing chemicals utilization, decreasing the environmental burden, improving leather quality. In this study, dendritic-linear polymers of PAMAM-Si 1G and PAMAM-Si 2G were applied to fatliquoring process, which were prepared by branching polysiloxane on the dendritic polyamide-amine (PAMAM). Then the emulsion properties, fatliquoring properties and fatliquoring mechanism were studied by EDS, SEM, XRD, TG and washing experiments. The conclusion was drawn that PAMAM-Si are weak alkali products with high emulsion stability. The particle size of PAMAM-Si 1G was 35.8 nm, and that of PAMAM-Si 2G was 26.7 nm. They can improve the softness, shrinkage temperature and physical and mechanical properties of leather. The softness of leather with PAMAM-Si 1G and PAMAM-Si 2G increased by 115.6% and 104.7% respectively. The shrinkage temperature of leather with PAMAM-Si 2G increased by 2.9℃. The Breaking elongation of leather with PAMAM-Si 1G and PAMAM-Si 2G increased by 38.6% and 32.4% respectively. At the same time, PAMAM-Si not only increased the distance and disorder of fiber but combined with collagen fiber through hydrogen bond, a certain amount of physical adsorption and covalent bond. Take-Away: 1. The dendritic-linear polymers of PAMAM-Si 1G and PAMAM-Si 2G were prepared by branching polysiloxane on the dendritic polyamide-amine (PAMAM). 2. PAMAM-Si can improve the softness, shrinkage temperature and physical and mechanical properties of leather. 3. PAMAM-Si not only increased the distance and disorder of fiber but combined with collagen fiber through hydrogen bond, a certain amount of physical adsorption and covalent bond