Thesis (S.T.L.)--Catholic University of America, 1993. / Includes bibliographical references (leaves 162-165).

Thesis (S.T.L.)--Catholic University of America, 1993. / Includes bibliographical references (leaves 162-165).

Smouldering combustion governs the burning of many materials in the built and natural environments. Smouldering is flameless, heterogeneous combustion which occurs when oxygen reacts with the surface of a solid fuel. Understanding the conditions which will result in the ignition and smouldering of a porous fuel is important and the phenomena involved are complex and coupled, involving heat and mass transfer, and chemical kinetics. This thesis reports experimental studies of the ignition, spread, suppression and emissions from reactions in porous media. Similar experimental techniques are shown in this thesis to be applicable when studying a wide range of solids which undergo self-sustaining reactions. This thesis is presented in a manuscript style. Each chapter takes the form of an independent paper which has been prepared for journal publication and as such, each chapter can stand on its own as a piece of research. A final chapter summarizes the findings and conclusions and suggests further areas of research. Chapter 1 presents a study of self-sustaining decomposition of ammonium nitrate containing inorganic fertilizer. This is of importance to the shipping industry which transports these materials in large quantities. Upon exposure to a heat source, ammonium nitrate may undergo exothermic decomposition which can propagate through the material, posing safety and economic threats. This reaction does not involve oxygenbased chemistry, but has many similarities to the propagation of a smoulder front in a porous material. Small-scale experiments to investigate the self-sustaining decomposition (SSD) behaviour of NPK (nitrogen, potassium, phosphorous) 16.16.16 fertilizer were undertaken. Experiments showed that this material will undergo self-sustaining decomposition and are used to formulate a reaction framework. Findings were applied to the events that occurred aboard the Ostedijk in 2007. Chapter 2 is a study of smoulder in polyurethane foam to study the relationship between sample size, critical heat flux and spread rate. Smouldering fires are the leading cause of residential fire deaths in developed countries and polyurethane foam is ubiquitous in the modern world. The critical heat flux for ignition was found to decrease with increasing sample size and the spread rate was found to be a function of the sample size, smoulder propagation depth and the applied heat flux. This is the first time that results on the effect of sample size on smouldering have been reported in the literature and these can be used to aid the extrapolation of small-scale flammability testing results to large scale scenarios. Chapter 3 presents an experimental investigation into the ignition of porous fuels by hot particles. This is related to the problem of spotting ember ignition in wildland fires which is a major, but poorly understood, spread mechanism. The process of spotting occurs in wildland fires when fire-lofted embers or hot particles land downwind, leading to ignition of new, discrete fires. The work studies the ignition of a fuel as a function of ember size and temperature. Metal particles are used as a proxy for burning embers and powdered cellulose to represent the forest fuel. Relationships between the size and temperature of the particle required for flaming and smouldering ignitions are found. These results are used to assess the ability of hot-spot ignition theory to determine the particle size–temperature relationship required for ignition of a cellulose fuel bed. Chapter 4 is an investigation into the suppression of smouldering coal. Subsurface coal fires are a significant global problem with fires in China alone estimated to consume up to 200 million tons of coal per year. As global demand for coal increases, accidental fires are a waste of a useful energy resource as well as a source of pollution and greenhouse gases. The results are the first attempt reported in the literature to study the suppression of these fires under controlled laboratory conditions. The ignition, spread and suppression of subsurface coal fires were studied using small-scale laboratory experiments. Time to ignition was seen to depend on particle size with small and large particles resulting in long times to ignition, while medium sized particles resulted in the shortest time to ignition. The maximum temperature, spread rate and mass lost were found to be independent of particle size above a critical particle size. The effectiveness of three systems for delivery of a suppression agent were assessed – direct injection, shower and spray. The effect of particle size on the water required for extinguishing using a spray was found to be weak. Chapter 5 presents an experimental investigation of the smouldering behaviour of peat. This is of particular interest in understanding the impact of smouldering fires on the earth system. The longer burn durations and different combustion dynamics of smouldering compared to flaming means that they have been shown to consume large amounts of biomass in, and contribute significantly to the emissions from, natural fires occurring in peatlands. The dynamics of smouldering peat in shallow, strong fronts was studied in the Fire Propagation Apparatus and a smoulder reaction framework with two burning regimes is presented. The first regime is peat smouldering and was found to be controlled by the applied heat flux and the second regime corresponded to char smouldering and was more sensitive to the flow of oxidizer. Chapter 6 complements Chapter 5 with an analysis of the CO and CO2 emissions for smouldering and flaming peat. This data can be used with large-scale measurement techniques to improve emission estimates. The emissions are found to be dependent of the burning regime and the type of combustion with flaming resulting in higher fluxes of CO2 and lower fluxes of CO compared to peat smouldering. Char smouldering resulted in the highest yields of CO and CO2. The large majority of emissions (85% of CO2 and 97% of CO) are released during the smoulder phase of the reaction. This highlights the differences in the chemical processes occurring under these two modes of combustion. Chapter 7 summarizes the research undertaken in this thesis and presents possible further work.

ABSTRACT   Context: Many websites today are very interactive and the users are getting used to sites that change hundreds of elements every second. Often a JavaScript framework is used to build the web site and with many changing elements on the site the need for a JavaScript framework that can handle the fast changes are needed. Each frameworks do it differently to achieving this but most of them do some manipulation with the Document Object Model (DOM).     Objectives: This research will show how fast the selected MCV like JavaScript frameworks (AngularJs, AngularJs 2.0, Aurelia, Backbone, Ember, Knockout, Mithril, Vue) can create, delete and update HTML elements on the screen.     Methods: This research have used Google Chromes TimeLine tool to measure the speed of the frameworks. The test involves creating a HTML table and fill it with a thousand rows of data with six columns. The tables content are tested to see how fast the frameworks can create, update and remove the elements.       Conclusions: Angular 2.0 almost achieved first place in all tests. Angular 1.5 did very good in the update tests and was good in the create elements test. Backbone and Ember did not do so well in the create and update tests but Backbone was the best framework in one of the delete tests. Aurelia got very good results and so did Vue which almost had the same values as Aurelia throughout the tests. Mithril and Knockout performed well in the create test which placed them in the middle among all the selected frameworks. When it came to the update tests Mithril and Knockout also found them self in the middle positions of all the frameworks.          Key Words: JavaScript, Framework, performance, Angular, Aurelia, Backbone,  Ember, Knockout, Mithril, Vue.

In this report, a number of different Javascript-frameworks have been compared. The study is conducted at CSN (Centrala studiestödsnämnden). The study consists of two main parts, an evalua- tion through the literature study and an evaluation of the implementa- tion. The first part of the survey has Javascript-frameworks Angular2, Aurelia, Ember, Meteor and React comparisons. Together with CSN, a few criteria have been developed which will then be awarded points between one and five depending on how well a Javascript-framework meets a specific criterion. Five points are given when the Javascript- framework meets the entire criterion, one point is given when it partial- ly meets the criterion. After the first part of the investigation, Angular2 and Aurelia found that they would move on to the implementation phase. The implementation consists of a couple of windows from the existing service "Mina tjänster". In the evaluate implementation measures time for implementation, web browsing time, and number of code rows. From this it was found that Aurelia has less number of code rows than Angular 2. The reading time for Angular 2 is three times longer than Aurelia. In the evaluation of how difficult it is to implement the two frameworks, Angular 2 is considered to be "Average" and Aurelia to "Hard". The Javascript-framework recommended for CSN is Angular 2. This is because much more documentation about Angular 2 is available, and the difficulty is lower for Angular 2. The startup of a project is also much easier in Angular 2, which means that it requires less time to get into the framework. / Sammanfattning: I denna rapport har ett par olika Javascript-ramverk jämförts. Studien är utförd på CSN (Centrala studiestödsnämnden). Undersökningen består av två huvuddelar, en utvärdering genom litteraturstudie samt en utvärdering av implementation. I första delen av undersökningen har Javascript-ramverken Angular2, Aurelia, Ember, Meteor och React jämförts. Tillsammans med CSN har ett par kriterier tagits fram som det sedan kommer att delas ut poäng mellan ett till fem beroende på hur väl ett Javascript-ramverk uppfyller ett specifikt kriterium. Fem poäng ges ut då Javascript-ramverket uppfyller hela kriteriet, ett poäng ges ut då det delvis uppfyller kriteriet. Efter första delen av undersökningen kom det fram till att Angular2 och Aurelia skulle gå vidare till implemente- ringsfasen. Implementeringen består utav ett par fönster från den befintliga tjänsten ”Mina tjänster”. I utvärderingen av implementation mäts tid för implementering, inläsningstid för webbapplikationen samt antalet kodrader. Ur detta konstaterades det att Aurelia har mindre antalet kodrader än Angular 2. Inläsning tiden för Angular 2 är tre gånger längre än Aurelia. Men i bedömningen om hur svårt det är att implementera de bägge ramverken bedöms Angular 2 till nivån ”Me- del” och Aurelia till ”Svår”. Det Javascript-ramverk som rekommende- ras till CSN är Angular 2. Detta grundas på att det finns betydligt mycket mer dokumentation om Angular 2, samt att svårighetsgraden är lägre för Angular 2. Uppstarten av ett projekt är även mycket enklare i Angular 2, vilket betyder att det kräver mindre tid för att sätta sig in ramverket.

JavaScript is breaking ground with the wave of new client-side frameworks. However, there are some key differences between some of them. One major distinction is the data flow pattern they applying. As of now, there are two predominant patterns used on client side frameworks, the Two-way data flow pattern and the Unidirectional data flow pattern. In this research, an empirical experiment was conducted to test the data flow patterns impact on maintainability. The scope of maintainability of this research is defined by a set of metrics: Amount of lines code, an amount of files and amount of dependencies. By analyzing the results, a conclusion could not be made to prove that the data flow patterns does affect maintainability, using this research method.