Coal Pyrolysis Distribution

Coal pyrolysis is a complex process involving a large number of chemical reactions. The most accurate and up to date approach to modeling coal pyrolysis is to adopt the Distributed Activation Energy Model (DAEM) in which the reactions are assumed to consist of a set of irreversible first-order reactions that have different activation energies and a constant frequency factor. The differences in the activation energies have usually been represented by a Gaussian distribution. This thesis firstly compares the Simple First Order Reaction Model (SFOR) with the Distributed Activation Energy Model (DAEM), to explore why the DAEM may be a more appropriate approach to modeling coal pyrolysis. The second part of the thesis uses the inverse problem approach together with the smoothing function (iterative method) to provide an improved estimate of the underlying distribution in the wide distribution case of the DAEM. The present method significantly minimizes the error due to differencing and smoothes the chopped off parts on the underlying distribution curve

Kinetic Monte Carlo (KMC) Algorithm for Nanocrystals

This thesis uses the kinetic Monte Carlo (KMC) algorithm to examine the growth morphology and structure of nanocrystals. Crystal growth in a supersaturated gas of atoms and in an undercooled binary melt is investigated. First, in the gas phase, the interplay of the deposition and surface diffusion rates is studied. Then, the KMC algorithm is refined by including solidification events and finally, by adding diffusion in the surrounding liquid. A new algorithm is developed for modelling solidification from an undercooled melt. This algorithm combines the KMC method, which models the change in shape of the crystal during growth, with a macroscopic continuum method that tracks the diffusion of material through solution towards the crystal. For small length and time scales, this approach provides simple, effective front tracking with fully resolved atomistic detail of the crystal-melt interface. Anisotropy is included in the model as a surface diffusion process and the growth rate of the crystal is found to increase monotonically with increase in the surface anisotropy value. The method allows for the study of multiple crystal nuclei and Ostwald ripening. This method will aid researchers to explain why certain crystal shapes form under particular conditions during growth, and may enable nanotechnologists to design techniques for growing nanocrystals with specific shapes for a variety of applications, from catalysis to the medicine field and electronics industry. This will lead to a better understanding of the atomistic process of crystal growth at the nanoscale

Information architecture using best merge method, category validity, and multidimensional scaling for open card sort data analysis

Open card sorting is a widely used method in HCI for the design of user-centered Information Architectures (IAs). This article proposes a new algorithm that combines the best merge method (BMM), category validity technique (CVT), and multidimensional scaling (MDS) to explore, analyze and visualize open card sort data. A study involving 20 participants and 41 cards explored the IA redesign of a university’s website. The collected data were analyzed using two popular methods employed in the quantitative analysis of open card sort data (i.e., hierarchical clustering, K-means) and the proposed algorithm. It was found that the latter provides increased IA insights compared to the existing methods. Specifically, the proposed algorithm can expose hidden patterns and relationships amongst cards and identify complexities. We also found that the proposed algorithm produces better initial clusters, which have a direct effect on the final clustering quality

Assistive technologies: saviour of Mathematics in higher education

The pervasion and inclusion of new technologies into teaching and learning processes are continuously changing the higher education landscape. Selected and specific technologies termed as “assistive technologies” are being used as key tools for enabling students to access education and actively and independently participate in the education process, improving learning and supporting inclusive education. This paper presents students’ perception of the use of various assistive technologies such as mobile learning, tablet learning, lecture capture, gamification, and online intelligent systems that have been developed for learning and student support at a higher education institute. There is also a broad discussion on how these can be adopted and adapted in mathematics learning in higher education. It is well documented that students have low-esteem toward or while doing the subject and have math phobia, particularly in higher education. An online questionnaire on the students’ perception of using assistive technologies was deployed to the mathematics students. The results show that assistive technologies are indeed a saviour of mathematics with a significantly positive attitude garnered toward using them for learning mathematics

Information architecture: using K - means clustering and the best merge method for open card sorting data analysis

Open card sorting is a well-established method for discovering how people understand and categorize information. This paper addresses the problem of quantitatively analyzing open card sorting data using the K-means algorithm. Although the K-means algorithm is effective, its results are too sensitive to initial category centers. Therefore, many approaches in the literature have focused on determining suitable initial centers. However, this is not always possible, especially when the number of categories is increased. This paper proposes an approach to improve the quality of the solution produced by the K-means for open card sort data analysis. Results show that the proposed initialization approach for K-means outperforms existing initialization methods, such as MaxMin, random initialization and K-means++. The proposed algorithm is applied to a real-world open card sorting dataset, and, unlike existing solutions in the literature, it can be used with any number of participants and cards

Talanoa he vā māfana: an indigenous Tongan approach to leadership

Based on a study of Tongan leadership practices in the New Zealand Public Service, a question was asked as to what could be an appropriate approach to exploring leadership from a Tongan perspective. This paper discusses talanoa he vā māfana as a concept useful in developing an approach upon which to explore the ideas of leadership that are exercised by Kakai Tonga (Tongan people) across given contexts. Drawing upon Tongan language and culture, talanoa he vā māfana is unpacked through three different ways or forms of talanoa – talanoa mo e loto (talking from the heart and soul), pō talanoa (peaceful dialogue), and talatalanoa (ongoing dialogue). Talanoa he vā māfana extends beyond the existing talanoa research approach, enabling conversations that engage with and embrace the loto, heart and soul of the people. It also provides a Tongan perspective on, and new insights into qualities of meaningful leadership within non-indigenous organisations

Card sorting: Practical guidance from a Pacific perspective

Most higher education institutions do employ a website to publish the information they wish to communicate to their users in the most efficient way possible. However, many disputes come to users when using the website due to lack of both usability standard and information architecture design. Card sorting is a great first step to designing and re-designing the structure of a website to be aligned with users’ expectation. This paper provides a practical guidance of card sorting from a Pacific perspective based on the authors’ reflections on their experience from using card sorting to explore user perceptions towards revamping the quality of the University of the South Pacific’s Research Office website. Building a website that involves users in defining the information architecture is the best possible way to be successful in terms of website usability. The authors’ reflections have shown that card sorting with and for Pacific people can be more meaningful when the subjective meaning of their card sorting and their inseparable relationships with the researcher are taken into account. This offers new insights into contextualising card sorting in the Pacific

Information Architecture (IA): Using multidimensional scaling (MDS) and k-means clustering algorithm for analysis of card sorting data

We present a method for visualizing and analyzing card sorting data aiming to develop an in-depth and effective information architecture and navigation structure. One of the well-known clustering techniques for analyzing large data sets is with the k-means algorithm. However that algorithm has yet to be widely applied in analyzing card sorting data sets to measure the similarity between cards and result displays using multidimensional scaling. The multidimensional scaling, which employs particle dynamics to the error function minimization, is a good candidate to be a computational engine for interactive card sorting data. In this paper, we apply the combination of a similarity matrix, a kmeans algorithm, and multidimensional scaling to cluster and calculate an information architecture from card sorting data sets. We chose card sorting to improve an information architecture. We used a spreadsheet table to identify cluster categories and their components. The proposed algorithm handled the overlaps between cards in the card sorting data quite well and displayed the results in a basic layout showing all clusters and card coordinates. For outliers the algorithm allows grouping of single cards to their closest core clusters. The algorithm handled outliers well choosing cards with the strongest similarities from the similarity matrix. We tested the clustering algorithm on real world data sets and compared to other techniques. The results generated clear knowledge on relevant usability issues in visualizing information architecture. The identified usability issues point to a need for a more in-depth search of design solutions that are tailored for the targeted group of people who are struggling with complicated visualizing techniques. This study is for people needed support to easily visualize information architecture from data sets

Modelling microwaves in Bauxite

Sending microwaves through bauxite ore allows almost continuous measurement of moisture content during offload by conveyor belt from a ship. Data and results from a microwave analyser were brought to a European Study Group with Industry at the University of Limerick, with the over-arching question of whether the results are accurate enough. The analyser equipment uses linear regression against phase shifts and signal attenuation to infer moisture content in real time. Simple initial modelling conducted during the Study Group supports this use of linear regression for phase shift data. However, that work also revealed striking and puzzling differences between model and attenuation data. We present an improved model that allows for multiple reflections of travelling microwaves within the bauxite and in the air above it. Our new model uses four differential equations to describe how electric fields change with distance in each of four layers. By solving these equations and taking reflections into account, we can accurately predict what the receiving antenna will pick up. Our new solution provides much-improved matches to data from the microwave analyser, and indicates the deleterious effects of reflections. Modelled signal strength behaviour features a highly undesirable noninvertible dependence on bauxite mixture permittivity. Practical measures that might be expected to reduce the effects of microwave reflections and improve the accuracy of microwave analyser results are suggested based on our improved model solution. This modelling approach and these results are anticipated to extend to the analysis of moisture content during transport on conveyor belts of other ores, slurries, coal, grains and pharmaceutical powders, especially when the depth of the conveyed material is variable

Being Constructive in Doing Mathematics

The traditional method of doing mathematics is primarily based on classical logic. By doing mathematics constructively, we mean doing mathematics using intuitionistic logic which can be seen as a generalisation of classical logic. Carefully selected examples are used to demonstrate the notion of constructivity in mathematics. The emphasis lies in the importance of the computational content of mathematics