Magnesium hydroxide, a stable flame retardant, can be obtained by mining or by the hydration of magnesium oxide. In this study, the effect of different hydrating agents on the pH of the hydrating solution, rate of hydration of MgO to Mg(OH)2 and product surface area were studied as a function of the temperature of hydration. Ammonium chloride, magnesium acetate, magnesium nitrate, nitric acid, acetic acid, water, magnesium chloride, sodium acetate and hydrochloric acid were used as hydrating agents. The hydration experiments were carried out in a water bath between 30 - 80 oC for 30 minutes. Dried MgO samples were introduced to the hydrating solution and the slurry was stirred at a constant speed. At the end of each experiment, the slurry was vacuum filtered, washed with water, dried at 200 oC and hand ground. The products were then characterized by TGA, XRF, XRD and BET surface area analyses. There was not a significant difference in the hydration behaviour of the hydrating agents up to 50 oC, where less than 10 % of magnesium hydroxide was formed. When compared to the hydration in water, all the hydrating agents with the exception of sodium acetate showed a significant increase in the degree of hydration. Sodium acetate formed the lowest amount of magnesium hydroxide, ranging between 1.2 and 12.2 % magnesium hydroxide. Hydrations performed in hydrochloric acid and magnesium nitrate formed the largest percentage (11.8 %) of magnesium hydroxide at 60 oC. Magnesium acetate, magnesium nitrate, magnesium chloride and hydrochloric acid seemed to be the most effective hydrating agents at 70 oC with the percentage magnesium hydroxide being formed ranging between 20.0 and 23.9 %. The amount of hydroxide formed doubled at 80 oC, with the largest percentage (56.7 %) formed from the hydration in magnesium acetate. The hydration reaction seemed to be dependent upon the presence of Mg2+ and acetate ions. It seemed that magnesium oxide hydration is a dissolution-precipitation process controlled by the dissolution of magnesium oxide. The results have also indicated that the pH and temperature of the hydrating solution strongly influence the degree of hydration. / Chemistry / M.Sc. (Chemistry)

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / This paper was prepared as part of the team design competition for a graduate level course given at the University of Canterbury, in Christchurch, New Zealand. It presents a high level design of a bobsled data acquisition system which is intended to aid athletes and coaches in achieving the maximum benefit from their time at the bobsled track. The system will measure every applicable aspect of the bobsled’s performance down the track, and provide real time and near real time feedback for the athletes and the coach. This system implements an inertial navigation and position system, monitors wind speed, measures the drivers steering input and effort, measures individual pushing effort in the critical start stage of the run, and provides cue signals to the runners when to mount the sled. A robust packet format and error correction in conjunction with a E2ROM backup system ensure data integrity. The data is transmitted utilising a GMSK signalling scheme, operating at a frequency of 400MHz. A space conserving patch antenna is mounted on the bobsled and a leaky wave antenna placed alongside the track for the transmission system. A link budget and the error performance of the transmission system are analysed. A graphical front end at the coach’s base station provides real time data display and analysis.

International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The telemetry group has begun a new program in conjunction with Goddard Space Flight Center to investigate the possibilities of using parallel processing configurations for the real-time processing of Space Station data. In order to evaluate the potential configurations, a program based on using discrete-event simulation models is being used. This modeling software allows for generic configurations to be modeled and the relevant parameters to be modified to see the effects on performance. This paper represents a description of the work we will be undertaking over the next 18 months and the environment to be used in creating the simulation models at NMSU.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper was prepared as part of the team design competition for a graduate level course given at the University of Canterbury, in Christchurch, New Zealand. It presents a high level design of an automated telemetering system for tracking and monitoring a number of land-based animals as small as a rabbit. The primary purpose of the system is to monitor both desirable and undesirable species of wildlife in the New Zealand bush in order to better understand their living habits and environmental requirements. The typical conditions monitored are body temperature, moisture levels, light intensity, physical activity, and heart rate. All critical aspects of the telemetering system have been specified, including the sensors, transmitter/receiver, and telemetry packet and frame design. A calculation of the link budget for the system has been performed.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper was prepared as part of the team design competition for a graduate level course given at the University of Canterbury, in Christchurch, New Zealand. It presents a high level design of a snow avalanche telemetry system. The goal of the system is to provide data to better assess avalanche risk, and to assist in designing more effective protection measures in avalanche prone areas. The primary conditions monitored are air pressure, snow density, snow depth, snow temperature, wind velocity, wind direction, and ambient air temperature. All critical aspects of the telemetering system have been specified, including the sensors, transmitter/receiver, and telemetry frame design. Aspects of the system packaging and the link budget which are unique to the alpine environment are discussed.

A major goal in software engineering is to reduce the cost of maintaining software systems. Finding design methods which make software more easily maintainable has thus been one of the most prioritized challenges during the past decade. While mainstream software design has concentrated on maintainability, other software disciplines e.g. high-performance computing and high-availability systems, have developed other design methods which primarily support the quality attributes that are more important in their areas. More recently, demands have been made for high performance and high availability in typical mainstream software. At the same time, traditional high-performance and high-availability systems tend to incorporate more advanced business functionality, i.e. different software disciplines have started to converge. The situation is not unproblematic since the software design methods developed for achieving performance and availability may have been developed with a limited influence from maintainability, and vice versa. It is thus important to identify and analyze emerging design conflicts. In this thesis I have studied conflicts between maintainability design methods onthe one hand, and performance and availability methods and techniques on the other. I present the results of four case-studies involving four different applications. It is a characteristic of these applications that half of the system can be regarded as a telecommunications system and the other as a typical main-stream system, i.e. all systems make high demands on performance and availability but also very high demands on high maintainability. In studying these applications, I have identified two major conflicts: granularity in dynamic memory usage and source code size. My results show that these two conflicts can cause problems of such amplitude that some applications become unusable. I found that conflicts in certain situations are inherent; in other cases they can be avoided - or at least reduced - by adjusting the design methods used. I have also shown that conflicts may quite simply be a matter of misconceptions. Ten guidelines have been combined into a simple process with the aim of helping software designers to avoid and reduce conflicts. A method which automatically reduces the dynamic memory conflict in object-oriented applications written in C++ has been developed, implemented and evaluated. Finally, I have defined optimal recovery schemes for high availability clusters.

Both semantic web applications and individuals are in need of knowledge infrastructures that can be used in dynamic and distributed environments where autonomous entities create knowledge and build their own view of a domain. The prevailing view today is that the process of ontology evolution is difficult to monitor and control, so few efforts have been made to support such a controlled process formally involving several ontologies. The new paradigm we propose is to use an infrastructure mechanism that processes ontology change proposals from autonomous entities while maintaining user-defined consistency between the ontologies of these entities. This makes so called semantic autonomy possible. A core invention of our approach is to formalise consistency constraints as so called spheres of consistency that define 1) knowledge regions within which consistency is maintained and 2) a variable degree of proof-bounded consistency within these regions. Our infrastructure formalism defines a protocol and its computational semantics, as well as a model theory and proof theory for the reasoning layer of the mechanism. The conclusion of this thesis is that this new paradigm is possible and beneficial, assuming that the knowledge representation is kept simple, the ontology evolution operations are kept simple and one proposal is processed at a time.

Nowadays smartphones and smartphone-applications are a part of our daily life. There are variety of different operating systems in the market that are unalike, which are an obstacle to developers when it comes to developing a single application for different operating system. Furthermore, hybrid application development has become a potential substitute. The evolution of new hybrid approach has made companies consider hybrid approach as a viable alternative when producing mobile applications. This research paper aims to compare native and hybrid application development on a feature level to provide scientific evidence for researchers and companies choosing application development approach as well as providing vital information about both native and hybrid applications.This study is based on both a literature study and an empirical study. The sources used are Summon@BTH, Google Scholar and IEEE Xplore. To select relevant articles, the Snowballing approach was used, with Inclusion and Exclusion criteria’s.The authors concluded that native development is a better way to develop more advanced applications which uses more device-hardware, while hybrid is a perfectly viable choice when developing content-centric applications.

An enhanced method in optimization rooted in direct collocation is formulated to treat the finite set optimal control problem. This is motivated by applications in which a hybrid dynamical system is subject to ordinary differential continuity constraints, but control variables are contained within finite spaces. Resulting solutions display control discontinuities as variables switch between one feasible value to another. Solutions derived are characterized as optimal switching schedules between feasible control values. The methodology allows control switches to be determined over a continuous spectrum, overcoming many of the limitations associated with discretized solutions. Implementation details are presented and several applications demonstrate the method’s utility and capability. Simple applications highlight the effectiveness of the methodology, while complicated dynamic systems showcase its relevance. A key example considers the challenges associated with libration point formations. Extensions are proposed for broader classes of hybrid systems. / text

Web applications are widely used for email, online sales, auctions, collaboration, etc. Most of today’s highly-available web applications implement fault tolerant protocols in order to tolerate crash faults. However, recent system-wide failures have been caused by arbitrary or Byzantine faults which these applications are not capable of handling. Despite the abundance of research on adding Byzantine fault tolerance (BFT) to a system, BFT systems have found little use outside the research community. Reasons typically cited for this are the difficulty in implementing such systems and the performance overhead associated with them. While most research focuses on improving the performance or lowering the replication cost of BFT protocols, little has been done on making them easy to implement. The goal of this thesis is to evaluate the viability of BFT web applications and show that, given the right abstraction, it is viable to build a Byzantine fault tolerant web application without extensive reimplementation of the web application. In order to achieve this goal, it demonstrates a BFT implementation of the Apache Tomcat servlet container and the VQWiki web application by using the UpRight BFT library. The UpRight library provides abstractions that make it easy to develop BFT applications and we leverage this abstraction to reduce the implementation cost of our system. Our results are encouraging — less than 2% of the original system needs to be modified while still retaining all the functionality of the original system. Given the design trade-offs that we make in implementing the system, we also get comparable performance, indicating that implementing BFT is a viable option to explore for highly-available web applications. / text