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Aldhahyani, Ammar. "Implementation of FaDO in React.js : Implementation of FaDO in React.js." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-438670.
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This report describes the implementation of FaDO as a REACT.JS web-based tool. FaDO is a machine learning method for real-time fraud detection: it flags (financial)transactions as either fraudulent or normal in a real-time fashion. FaDO implementssemi-supervised machine learning for this task: in semi-supervised learning, only a small portion of the presented data needs to be labeled. This tool is designed as a filter that works together both with existing automatic fraud filters and human experts. The contribution of this work is a dynamical webpage that implements and demonstrates the approach. Herefore, the REACT framework and the JSX programming language were used. The emphasis of this tool is put on real-time in-browser processing of all data. In order to illustrate the tool, a realistic artificial transaction generator was implemented. The tool then allows to organise different fraud filters to select fraudulent transactions from this high-frequency stream. This report gives also preliminary key performance indicators (KPIs) of the approach. A comparison to a realistic hand-crafted expert system is given.
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Кулиба, М. В. "Розробка кабінету користувача для обліку показань лічильників води із використанням платформи Google Firebase та фреймворку React.js." Thesis, Чернігів, 2020. http://ir.stu.cn.ua/123456789/23491.
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Кулиба, М. В. Розробка кабінету користувача для обліку показань лічильників води із використанням платформи Google Firebase та фреймворку React.js : випускна кваліфікаційна робота : 123 "Комп’ютерна інженерія" / М. В. Кулиба ; керівник роботи О. В. Красножон ; НУ "Чернігівська політехніка", кафедра інформаційних та комп’ютерних систем. – Чернігів, 2020. – 49 с.Сьогодні важко уявити наше життя без інтернету. Інтернет сторінки поступово вилучають з обігу паперові документи і джерела інформації. З кожним роком набирає популярності система он-лайн кабінетів платників комунальних послуг з метою своєчасного обліку їх надання та отримання. Для підприємств, що надають комунальні послуги є актуальним своєчасний облік їх надання та використання споживачем. Створення та експлуатація он-лайн кабінетів споживачів та платників комунальних послуг сприяє вдосконаленню обліку наданих комунальних послуг, збільшенню якості надання послуг та, відповідно, збільшення прибутку. На сьогодні JavaScript є найпопулярнішою мовою програмування, що обумовлено, як на мою думку, невибагливістю мови – для того, аби виконати написаний скрипт, в найпростішому випадку достатньо просто відкрити сторінку консолі в браузері. До того ж, існує велика кількість сторонніх бібліотек, які дають змогу для вживаних тривіальних задач використати існуючий код, тим самим, пришвидшити розробку. JavaScript абсолютно безкоштовний, як і бібліотеки для нього (на відміну від інших популярних мов програмування для веб, наприклад, php). Для того, аби адаптувати мову для великих проектів, зробити програмування більш комфортним, існує велика кількість фреймворків, що дає величезну перевагу і гнучкість для розробника, тим самим, закріпляючи мову на 1-му місці у списку найбільш вживаних. Об’єкт дослідження. Кабінет користувача для обліку показань лічильників води. Предмет дослідження. Програмні засоби, які дозволяють створити кабінет користувача для обліку показань лічильників води. Гіпотеза дослідження. Використовуючи платформу Google Firebase та фреймворку React.js для створення кабінету користувача для обліку показань лічильників води отримуємо найбільш якісний результат за найкоротший час. Мета. Розробка кабінету користувача для обліку показань лічильників води із використанням платформи Google Firebase та фреймворку React.js. Продемонструвати можливості React.js фреймворку для створення веб-застосунків. Продемонструвати можливості Google firebase, як хостингу для веб-застосунків. Продемонструвати взаємодію React.js, Google firebase, Google API для створення повноцінного веб-застосунку з розміщення останнього в інтернеті як самостійний інтернет ресурс.
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Ahmed, Abukar. "Jämförelse mellan Joomla och React.js utifrån svarstid på en bokhandel webbsida." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19898.
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I denna studie jämförs JavaScript-biblioteket React mot Joomla på en e-commerce webbsida. Tillämpningen på e-commerce webbsidan är bokhandel. I implementationen skapades det två webbsidor. En med React och den andra med Joomla. Webbsidan använder sig även av Bootstrap som CSS-ramverk för att få samma layout. Detta är viktigt då mätningen utförs i en kontrollerad miljö där det är viktigt att allting utgår ifrån samma förutsättningar. Mätningen sker genom ett eget skript som körs genom Tampermonkey tillägget i Chrome. Resultatet av mätningarna visas senare i grafer som indikerar att React har en mycket snabbare svarstid jämfört med Joomla-webbsidan. I framtida arbeten går det att öka antalet produkter och innehåll och göra webbsidan mer verklighetsbaserat. Det går även att byta tillämpningstema till en elektronikwebbsida där det förmodligen skulle behöva innehålla fler bilder och även videoklipp.
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Кривопуск, О. О. "Модульна мультисенсорна система для моніторингу навколишнього середовища на базі Аarduino." Thesis, Чернігів, 2020. http://ir.stu.cn.ua/123456789/23416.
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Кривопуск, О. О. Модульна мультисенсорна система для моніторингу навколишнього середовища на базі Аarduino : випускна кваліфікаційна робота : 123 "Комп’ютерна інженерія" / О. О. Кривопуск ; керівник роботи С. С. Стасюк ; НУ "Чернігівська політехніка", кафедра інформаційних і комп’ютерних систем. – Чернігів, 2020. – 61 с.У роботі описаний процес та результати розробки (реалізації)модульної мультисенсорної системи. У процесі реалізації було розроблено готову систему для вимірювання параметрів навколишнього середовища. Також була використана технологія react.js. В якості сервера було використано вбудований сервер node.js. Система виконує наступні основні функції: - прийом значень з датчиків; - передача результатів вимірювання на вебсторінку; - побудова графіків і відображення на вебсторінці. Результат розробки оформлений у вигляді програмного проєкту. Подальший розвиток роботи можливий у бік удосконалення графічного інтерфейсу користувача.
In the process of implementation, a ready-made system for measuring environmental parameters was developed. React.js technology was also used. The embedded node.js server was used as the server. The system performs the following main functions: - reception of values from sensors; - transfer of measurement results to the web page; - plotting and displaying on a web page. The result of the development is designed as a software project. Further development of work is possible in the direction of improving the graphical user interface
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Федотова, Н. А. "Веб-сайт дитячої музичної школи ім. П.І. Чайковського м. Тростянець." Master's thesis, Сумський державний університет, 2021. https://essuir.sumdu.edu.ua/handle/123456789/81985.
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Дипломна робота складається зі вступу, чотирьох розділів, висновка, списку літератури та додатків.
У першому розділі виконаний детальний аналіз предметної області для обґрунтування потреби наявності веб-сайту для навчально-виховного закладу та проведений експертний аналіз існуючих веб-сайтів музичних шкіл на території України.
Другий розділ присвячений деталізації мети проекту, визначенню переліку задач для реалізації мети та аналізу засобів реалізації.
У третьому розділі було проведено проектування проекту з точки зору його розробки та використання, було розроблено діаграма варіантів використання.
Четвертий розділ присвячений детальному опису реалізації веб-сайту: прототипування веб-сайту, розробка статичного додатку, додавання серверу, розробка динамічного додатку, розробка панелі адміністратора.
Результатом дипломної роботи є веб-сайт, що дозволить покращити показник комунікації з батьками та учнями школи.
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Савичев, И. Н., and I. N. Savichev. "Разработка клиентской части веб-приложения «Мониторинг IT-конференций» : магистерская диссертация." Master's thesis, б. и, 2021. http://hdl.handle.net/10995/100808.
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Выпускная квалификационная работа 56 страниц, 19 рисунков, 11 источников, 8 приложений. Цель работы – разработка клиентской части веб-приложения «Мониторинг IT-конференций». В процессе работы был проведён анализ популярных фреймворков для веб-разработки, настроена интеграция с серверами CDN на базе сервиса Surge, создан Docker-образ с веб-приложением, настроена интеграция с GitHub Actions для CI/CD, настроен клиентский и серверный мониторинги на базе Sentry. В результате ВКР разработана клиентская часть на базе фреймворка Next.js для веб-приложения «Мониторинг IT-конференций».Final qualification work 56 pages, 19 figures, 11 sources, 8 appendices. The purpose of the work is to develop the client part of the web application "Monitoring of IT conferences". In the process, we analyzed popular frameworks for web development, configured integration with CDN servers based on the Surge service, created a Docker image with a web application, configured integration with GitHub Actions for CI/CD, configured client and server monitoring based on Sentry. As a result of the final qualifying work, the client part was developed on the basis of the Next framework.js for the IT Conference Monitoring web application.
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Madaj, Tomáš. "Výkonnostní testy pro chytré TV, set-top boxy a herní konzole." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2018. http://www.nusl.cz/ntk/nusl-386024.
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Cílem této práce je vytvořit nástroj pro vývoj aplikací na určité minoritní platformy, primárně Smart TV a HbbTV. Ty jsou implementovány v klienském JavaScriptu. Cílovou skupinou jsou tedy vývojáři takových aplikací, nikoli koncoví uživatelé. Zmíněný nástroj bude mít za cíl zjednodušit a urychlit vývojové procesy, hlavně ladění výkonu aplikací.
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Suomi-Olsson, Oskar. "Integration av webbaserat bokningssystem." Thesis, Mittuniversitetet, Institutionen för data- och systemvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39864.
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Företaget M Hälsa Träning behövde ett bokningssystem där kunder kunde boka träff med personalen, systemet skulle integreras i deras redan befintliga webbsida. Den befintliga webbapplikationen byggde på ett CMS för hantering av data. Tidbokningssystemet behövde anpassas för att kunna användas tillsammans med CMS:et. Utvecklingen av systemet gjordes med webbramverket React.js samt en utbyggnad av redan befintlig webbserver arkitektur. Befintliga beroenden och verktyg användes i så stor utsträckning som möjligt. Utifrån M Hälsa Tränings beskrivning av önskad funktionalitet togs en kravlista för systemet fram. Reactdelen av systemet delades in i React komponenter som alla ansvarade för en specifik del av tidbokningssystemet. Komponenterna kommunicerade med ett API för att skicka och ta emot data. React redux användes för att hantera datat i reactdelen. Anpassningsbar data implementerades på servern i så stor utsträckning som möjligt för att kunna ändras i CMS:ets instrumentbräda. Implementeringen av funktionalitet på serversidan byggde på tidigare programmerares struktur och exempel. Resultatet av konstruktionen blev ett bokningssystem inbyggt i den existerande applikationen. Bokningssystemet är uppdelat i tre steg, en sida för att välja behandling, en kalender för att välja en tid och slutligen ett formulär för att fylla i personuppgifter och bekräfta bokning. Slutsatserna som kunde dras av arbetet var att denna tilläggsutveckling förde med sig både för och nackdelar, svårigheter så som okända och utdaterade verktyg och beroenden. Fel val av språk i och dålig planering av reactdelen. Fördelar med denna utveckling var den struktur och stomme som utvecklaren av M Hälsa Träning gjort, vilket förenklade utvecklingen av serverdelen då en tydlig struktur med goda exempel fanns att följa.
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Marosan, Ivan, and Yousef Namazi. "Creating custom APIs to solve shortcomings in existing JavaScript Front-End Frameworks." Thesis, Högskolan Kristianstad, Fakulteten för naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-20730.
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The technology of creating web-based applications has been expanding and making better user interfaces that can support many different focus groups, such as building a website that is flexible and easy-to-use for children and/or the elderly. Another expansion has been in the field of storages of data and connectivity. These technologies, however, have a steep learning curve for new developers. With the rise of these new techniques, a unique contemporary set of skills have been introduced, the Front-End, which is a layer that involves the presentation aspect of an application. React.js is a popular JavaScript framework for front-end development. It has become the most framework for user interface design. In today’s market there are several other frameworks that one can utilize for front-end solutions such as Angular v2 and Vue.js. The results of this thesis is the improvement on creating a developer friendly custom creation of unique elements. By following proper processes when using the API, one can learn and create their own custom API to their own liking. The API created is a basic GUI addition to React, which enables a Log-In interface that can be easily manipulated by following the thesis, and/or by tracing the steps in the code. This is useful for those that want to have a template GUI API.
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Farkaš, František. "Webového rozhraní pro ovládání prvků chytré domácnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442382.
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Táto práca sa zameriava na návrh a implementáciu riešenia API na zisťovanie ZeroConf/mDNS služieb v lokálnej sieti. Cieľom tohto API je spracovať zisťovanie služieb a poskytnúť koncové body API na komunikáciu s webovým uživateľským rozhraním. Okrem backendového riešenia sa práca zameriava aj na vytvorenie WordPress pluginu pomocou React.js na zobrazovanie údajov poskytnutých backendovým API koncovému používateľovi. Tento plugin zároveň umožňuje správcovi WordPress serveru umiestniť komponent používateľského rozhrania Service discovery na stránku s obsahom podľa výberu správcu.
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Isaksson, William. "Visuell skalbarhet hos webbaserade heatmaps : En jämförande studie av JavaScript-baserade ramverk." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-19900.
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Datavisualisering innebär förmågan att omvandla rådata till en visuell form. Visualiseringen medför fördelen att data blir enklare att tolka. En form av datavisualiseringsteknik är Heatmaps. Heatmaps används bland annat till att visualisera geospatial COVID-19 data i syfte att successivt tolka denna. För att lyckas med det behöver visualiseringen icccnneha god visuell skalbarhet. Visuell skalbarhet innebär förmågan att kunna visa stora datamängder vilket kan förbättras genom bland annat utritningstider och clustering. Denna studie utförs i syfte att ta reda på vilket av JavaScript-ramverken Vue.js och React.js som möjliggör bäst visuell skalbarhet. Ett tekniskt experiment genomförs i syfte att jämföra ramverken på visuell skalbarhet. Två artefakter sätts upp i form av heatmaps innehållande visualiserad geospatial pandemidata. Skalbarheten mäts sedan genom utritningstider och medelvärden. Resultatet antyder att Vue.js ger än bättre visuell skalbarhet än React.js, även om inte skillnaderna är signifikanta. I framtiden skulle undersökningen kunna utvecklas genom fler mätvariabler och fler ramverk.Det finns övrigt digitalt material (t.ex. film-, bild- eller ljudfiler) eller modeller/artefakter tillhörande examensarbetet som ska skickas till arkivet.
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Hallberg, Emil. "Evaluation of the Effectiveness of Implementing a UI Library in FinTech Applications." Thesis, Umeå universitet, Institutionen för datavetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184549.
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Implementing new technology into a complex software developing environment comes with many challenges in terms of code, user interface design, and developer experience. It is well-established that the pressing demand for security and regulations within financial technology makes it even more essential to implement new technologies with care and minimised risks. This work aims to determine the effectiveness of such implementations. Specifically, it evaluates the effectiveness of implementing a UI library in a FinTech application to find the most suitable approach. In this context, a UI library defines as a robust set of user interface components available in one place and a FinTech application as an application in financial technology with complex developing infrastructure. In order to successfully evaluate the effectiveness of implementing a UI library in a FinTech application, a thorough literature survey was performed to identify decisive factors relating to code quality, user interface, and developer experience. In a case study in which a FinTech company served as an example, a solution consisting of their product and UI library was developed. The solution was tested by collecting data from code evaluation, questionnaires, and interviews. The result shows that the solution has higher code quality, fulfils the FinTech UI requirements, and perceived as an improvement of the development infrastructure. On this basis, the utilised methodology and the recognised factors in this work should be taken into account to identify the most suitable approach when implementing a UI library in a FinTech application.
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Färholt, Fredric. "Refactoring Nordyr : ReactJS + Laravel." Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39100.
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This independent work includes refactoring a website application. In simpler sense, it means modernizing existing code by increasing its quality and making it more understandable; to exchange old knowledge of methods and concepts into something that is more relevant to its time. This refactoring has also meant to transform the UI into something that is more appealing, and more userfriendly. The website that has gone through the refactoring is Nordyr (”https://nordyr.com/”). Nordyr is a Nordic Film & Series Database that shares information about Nordic films and tv-series, and everyone involved. They also offer social tools such as user profiles and various tools to simplify the exploration and interaction between Nordic movies and consumers. This was made possible by using vanilla PHP, JavaScript/jQuery, and the MariaDB database for information storage and management. The implementation of the refactoring meant retaining PHP for the backend, but applying the Laravel framework, and likewise for JavaScript, but applying ReactJS (a powerful JavaScript library). Nordyr retains MariaDB for its information storage and management, however, its SQL queries have been adapted to Laravel’s query-builder and Eloquent ORM, which means that the majority of SQL queries have been rewritten and the majority of data tables are now represented by models. The restructuring of Nordyr has shown that the website now has the ability to scale better, and the development environment will also be more pleasant for those involved.Det här självständiga arbetet har innefattat att omstrukturera en hemsida. Det innebär i enklare mening att modernisera kod och öka dess kvalité; att byta ut äldre kunskaper om metoder och koncept till något som anses vara av mer relevans för sin tid. Refaktoreringen har också inneburit att dess UI gjorts om till att bli mer tilltalande och användarvänlig. Hemsidan som gått igenom refaktoreringen är Nordyr (”https://nordyr.com/”). Nordyr är en Nordisk Film- & Serie-databas som delar information om nordiska filmer och tv-serier och alla inblandade. De erbjuder även sociala verktyg som användarprofiler och diverse verktyg för att förenkla upptäckandet och interaktionen mellan nordiska titlar och konsumenter. Detta gjordes möjligt med hjälp av vanilj PHP, JavaScript/jQuery, och databasen MariaDB för informationslagring och hantering. Genomförandet av refaktoreringen innebar att behålla PHP för backend men tillämpa ramverket Laravel, och likaså för frontend, JavaScript stod kvar men ReactJS (”JavaScript bibliotek”) tillämpades. Nordyr behåller MariaDB, men dess förfrågningar i SQL har anpassats till Laravels query-builder och Eloquent ORM, vilket innebar att majoriteten av SQL frågor skrivits om och majoriteten av tabeller representeras nu av modeller (”Models”). Omstruktureringen av Nordyr har visat på att hemsidan nu har förmågan att skala bättre, och utvecklingsmiljön kommer även bli mer behaglig för de inblandade.
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Halliday, K. "Packed bed reactors." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599875.
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Conventional packed bed reactors of low tube to particle diameter ratio suffer from poor heat transfer near the tube wall, and also from increased axial dispersion compared with wide beds. In this dissertation the potential of a new reactor design aimed at overcoming these deficiencies is investigated. The radially-stratified bed provides more particles in the wall region to support improved heat transfer and also to flatten the voidage profile in an attempt to reduce the axial dispersion. An experimental study on the effect of stratification on voidage profiles using an image analysis technique showed that both the voidage and velocity profiles could be flattened. A study into the effect of different packing arrangements on axial dispersion has shown that the best arrangement for flattening the voidage profile can lead to over-compensation, resulting in channelling through the core and an increase in dispersion. However, a packing arrangement consisting of a binary mixture of large and small particles near the wall with the core of the bed packed solely with the larger, was shown to exhibit dispersion characteristics no worse than monosized packing. This same packing arrangement was also found to support improved heat transfer. At Rep > 1100 the heat transfer coefficient appropriate to the one-dimensional plug flow model was shown to increase by ca. 15%. A novel analysis of the one-dimensional reactor model has shown that use of a stratified bed of the same voidage, heat transfer coefficient, tube diameter, and feed flowrate as a monosized bed, results in a pressure drop which is 57% of that across a conventional bed of the same bed length. A further advantage of the stratified bed is that, on average, the catalyst particles are nearer the wall than in the conventional monosized bed. The magnitude of this and the other advantages was assessed by simulation of a reaction performed at high Reynolds numbers, the partial oxidation of ethylene. For this purpose, a new, plausible but simple two-dimensional model of the packed bed reactor was devised. A stratified bed was predicted to then have a pressure drop only some 34% of that of a conventional bed for the same overall conversion. This further reduction of some 23% in pressure drop stems largely from the reduction in packed length necessary to achieve a stipulated conversion. Alternatively, for the same selectivity, a stratified bed could reduce the pressure drop to about half that of a conventional bed of the same voidage. The potential of this novel design has thus been demonstrated: the next stage is optimisation.
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Wan, Yu Shan Susanna. "Zeolite microstructured reactors." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405836.
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Song, Peng. "Microengineered electrochemical reactors." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709449.
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Giraudeau, Franck. "Hydrogen in pressurized reactors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0019/NQ46292.pdf.
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Hoffman, Edward A. "Low activation tokamak reactors." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/16679.
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FANNEAU, BELLENGER VALERIE. "Synthese de reactifs thiocylants fonctionnels et modification d'enzymes a l'aide de ces reactifs." Caen, 1989. http://www.theses.fr/1989CAEN2023.
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Ce travail decrit la synthese de reactifs thioacylants originaux et leur utilisation pour la modification des groupements amines lateraux (-nh#2) des residus lysines de deux proteases, la papaine et l'enzyme de mucor pusillus. La synthese des reactifs employes a porte sur des dithioesters et quelques dithioacides repondant aux criteres suivants: solubilite suffisante en milieu aqueux tamponne; presence d'une fonction ionisable ou reactive dans la chaine. Nous avons prepare des dithioesters -fonctionnels (acide carboxylique, acide phosphone et thio) ainsi que des sels de dithioacides et bis(dithioacides). Les fonctions introduites sont capables de modifier le comportement de la proteine en fonction du ph. Les enzymes modifiees et natives sont comparees par dosage des amines libres, le deplacement du maximum de l'absorption en uv-visible et la mesure de leur activite proteolytique specifique et non specifique. La modification de la papaine avait pour but d'etudier les effets produits par de telles modifications. Nous avons observe des differences de comportement en fonction de la structure chimique du residu introduit (nature de la fonction et hydrophobie de la chaine). Les modifications de l'enzyme de mucor pusillus ont permis d'agir sur le rapport des activites proteolytiques pour orienter l'action de l'enzyme vers une plus grande specificite (action coagulante envers le lait en augmentation relative par rapport a l'action proteolytique globale)
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Whitton, Rachel Louise. "Algae reactors for wastewater treatment." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10289.
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The onset of the Water Framework Directive (WFD) will challenge water utilities to further reduce their wastewater phosphorus discharges to < 0.5 mg.L- 1. Whilst conventional treatments, such as chemical dosing, are able to meet these new discharge consents, the strategies are representative of a linear economy model where resources are unrecovered and disposed. An alternative solution which can contribute to the aspiration of a circular economy is microalgae. Microalgae are ubiquitous in wastewater environments and assimilate phosphorus during their growth, to residual concentrations complementary of the WFD. Furthermore, microalgal biomass can be anaerobically digested to produce biomethane offering the potential for an energy neutral approach. However, uptake of microalgal systems are lacking in the UK through limited knowledge of operation; and the belief that such solutions are synonymous to large, shallow open ponds with extensive treatment times. The development of alternative microalgal reactors are increasingly investigated to overcome these implementation challenges. Of these, immobilised microalgae has shown great potential; and whilst within its infancy demonstrates the greatest opportunity for development and optimisation. This thesis determines the critical operational parameters that influence the remediation efficacy of immobilised microalgae for tertiary nutrient removal; including species selection, biomass concentration, treatment period and lighting; with recommendations for optimal performance. These recommendations are then applied to the design and operation of an immobilised bioreactor (IBR) to understand the key design and operating components that influence the overall economic viability. In doing so, the potential for an IBR to be economically viable, within the next decade, in comparison to traditional approaches are discussed.
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Urseanu, Maria Ioana. "Scaling up bubble column reactors." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/83970.
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Mead, Richard Norman. "Emulsion copolymerization in continuous reactors." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/11030.
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Bennett, Chris. "Monolith reactors for automobile catalysts." Thesis, University of Bath, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236643.
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Chowdhury, A. T. M. Shofiqui Islam. "Modelling of trickle bed reactors." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352957.
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Tomlinson, David. "Stability of catalytic plate reactors." Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337374.
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Gobby, Darren. "Design of catalytic microengineered reactors." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272329.
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SAILER, RAINER. "Nouvelles sources ponctuelles d'ions reactifs." Paris 11, 1996. http://www.theses.fr/1996PA112396.
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Ce memoire decrit la mise en uvre et la caracterisation de sources d'ions ponctuelles originales, destinees aux systemes a faisceaux d'ions focalises (fib). Ces sources font appel a des melanges de composes ioniques liquides, en particulier a des melanges de sels fondus. L'emission ionique a lieu a l'apex d'une pointe liquide, soutenue par un champ electrique. C'est pourquoi, par analogie avec les sources a metal liquide (lmis), l'appellation sources d'ions a composes ioniques liquides (licis) est proposee. Grace a une technologie innovante, une stabilite d'emission et des caracteristiques optiques qui satisfont aux exigences d'une colonne fib ont ete obtenues. Une etude de la distribution energetique et de la densite de courant angulaire a mis en evidence des proprietes tout a fait comparables aux lmis (une largeur energetique inferieure a 7 ev, et des densites de courant de l'ordre 10 a/sr). Les licis, fonctionnant a des tensions d'extraction comprises entre 2,5 kv et 3,5 kv, produisent une large gamme d'especes d'ions positifs et negatifs. Une serie de telles sources a ete caracterisee par spectrometrie de masse. Ces experiences ont revele une presence abondante d'ions reactifs mono-atomiques, tels que les alcalins et les halogenes, ainsi que des spectres riches en ions moleculaires. L'un des resultats majeurs de ce travail est la focalisation fine des ions cl-, no3-, o- ainsi que toute une serie d'autres especes negatives, ce qui n'avait pas ete fait auparavant. Ce memoire montre l'interet de ces systemes, tant au plan des processus physiques mis en jeu qu'au niveau des applications (microfabrication pour gravure fib, implantation ionique locale, micro-analyse (sim, sims, rbs), preparation d'echantillons pour sem, tem, ou analyse auger)
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CHARGY, DIDIER. "Etude numerique d'ecoulements reactifs transsoniques." Marne-la-vallée, ENPC, 1991. http://www.theses.fr/1991ENPC9104.
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Le travail presente dans cette these porte sur l'etude numerique d'ecoulements reactifs en regime transsonique. Le modele mathematique pour resoudre ces ecoulements est constitue des equations d'euler multi-especes ecrites pour un melange de gaz parfaits auxquels nous ajoutons les termes modelisant les effets diffusifs et les effets dus a la combustion. Pour resoudre numeriquement le systeme d'equations ainsi defini, nous utilisons une formulation mixte elements finis-volumes finis basee sur la methodologie muscl et utilisant des fonctions de flux numeriques decentres. Pour le traitement des conditions aux limites, on utilise des flux numeriques adaptes aux ecoulements multi-especes qui traitent les frontieres ou l'ecoulement est subsonique ou supersonique. A l'aide de ce schema on etudie differents problemes monodimensionnels de detonation stable et instable ainsi que des problemes bidimensionnels d'interaction reactive de jets et de flamme de diffusion. La difficulte des cas test etudies avec des rapports de pression parfois superieurs a 30 prouve la robustesse de la methode. De plus, l'utilisation de la methode muscl associee a des maillages fins obtenus par raffinement statique ou dynamique conduit a des solutions numeriques precises et sans oscillations. Pour s'affranchir des difficultes liees a la disparite des echelles temporelles qui apparaissent dans ces ecoulements, on propose differents schemas explicites et implicites par decomposition des operateurs qui permettent (tout en conservant une solution instationnaire de bonne qualite) des gains superieurs a 5 par rapport a l'explicite
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Wu, Jin Jwang Flagan Richard C. "Powder synthesis in aerosol reactors /." Diss., Pasadena, Calif. : California Institute of Technology, 1987. http://resolver.caltech.edu/CaltechETD:etd-06152006-074336.
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Li, Xiang. "Computational analysis of ultraviolet reactors /." Online version of thesis, 2009. http://hdl.handle.net/1850/11175.
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Bhatelia, Tejas Jagdish. "Novel reactors for multiphase processes." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/2418.
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Process intensification tools, such as the capillary reactor, offer several benefits to the chemical process industries due to the well-defined high specific interfacial area available for heat and mass transfer, which increases the transfer rates, and due to low inventories, they also enhance the safety of the process. This has provided motivation to investigate three such tools, namely the capillary microreactor, spinning disc and rotating tube reactors, in this study.The gas-liquid slug flow capillary microreactor intensifies reactor performance through internal circulation caused by the shear between the continuous phase/wall surface and the slug axis, which enhances the diffusivity and consequently increases the reaction rates. However, integrating the complex hydrodynamics of this reactor with its chemical kinetics is a mathematically challenging task. Therefore, in this study, a simple-to-complex approach, using a set of state-of-the-art computational fluid dynamic tools, has been used. Firstly, simulations were performed without any chemical reaction to ascertain the extent of slug flow regime. The model also clearly captured the slug flow generation mechanism which can be used to structurally optimize the angle of entry in these reactors. Finally, the hydrodynamic model was also capable of estimating the pressure drop and slug lengths. After successfully simulating the hydrodynamics of the system, a reaction model was incorporated to study the chemical reaction kinetics. The results were compared with the published experimental work and were found to be in good agreement.The spinning disc reactor utilizes the centrifugal and shear forces to generate thin liquid films characterized with intense interfering waves. This enables a very high heat transfer coefficients to be realized between the disc and liquid, as well as very high mass transfer between the liquid and the bulk gas phase. The waves formed also produce an intense local mixing with very little back mixing. This makes a spinning disc reactor an ideal contactor for multiphase processes. The focus of this study has been to elucidate the hydrodynamic behaviour of the liquid film flow over the horizontal spinning disc. Investigations were also performed to elaborate the local and overall hydrodynamic characteristics of a fully developed spinning disc reactor. Simulation results showed a continuous linear liquid film on the horizontal spinning disc and intense mixing performance in the annulus of the reactor around the disc surface. Finally, the film thickness data from the simulations were compared with the limited amount of data available for this novel process.Rotating tube reactor also uses centrifugal forces to generate the liquid film and a high degree of mixing along with an improved control over the reactant retention times. In this work we have conducted a CFD analysis to understand the hydrodynamics of this new technology for future developments.
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Bhatelia, Tejas Jagdish. "Novel reactors for multiphase processes." Curtin University of Technology, Science and Engineering, Department of Chemical Engineering, 2009. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=129027.
Full textAbstract:
Process intensification tools, such as the capillary reactor, offer several benefits to the chemical process industries due to the well-defined high specific interfacial area available for heat and mass transfer, which increases the transfer rates, and due to low inventories, they also enhance the safety of the process. This has provided motivation to investigate three such tools, namely the capillary microreactor, spinning disc and rotating tube reactors, in this study.The gas-liquid slug flow capillary microreactor intensifies reactor performance through internal circulation caused by the shear between the continuous phase/wall surface and the slug axis, which enhances the diffusivity and consequently increases the reaction rates. However, integrating the complex hydrodynamics of this reactor with its chemical kinetics is a mathematically challenging task. Therefore, in this study, a simple-to-complex approach, using a set of state-of-the-art computational fluid dynamic tools, has been used. Firstly, simulations were performed without any chemical reaction to ascertain the extent of slug flow regime. The model also clearly captured the slug flow generation mechanism which can be used to structurally optimize the angle of entry in these reactors. Finally, the hydrodynamic model was also capable of estimating the pressure drop and slug lengths. After successfully simulating the hydrodynamics of the system, a reaction model was incorporated to study the chemical reaction kinetics. The results were compared with the published experimental work and were found to be in good agreement.
The spinning disc reactor utilizes the centrifugal and shear forces to generate thin liquid films characterized with intense interfering waves. This enables a very high heat transfer coefficients to be realized between the disc and liquid, as well as very high mass transfer between the liquid and the bulk gas phase. The waves formed also produce an intense local mixing with very little back mixing. This makes a spinning disc reactor an ideal contactor for multiphase processes. The focus of this study has been to elucidate the hydrodynamic behaviour of the liquid film flow over the horizontal spinning disc. Investigations were also performed to elaborate the local and overall hydrodynamic characteristics of a fully developed spinning disc reactor. Simulation results showed a continuous linear liquid film on the horizontal spinning disc and intense mixing performance in the annulus of the reactor around the disc surface. Finally, the film thickness data from the simulations were compared with the limited amount of data available for this novel process.
Rotating tube reactor also uses centrifugal forces to generate the liquid film and a high degree of mixing along with an improved control over the reactant retention times. In this work we have conducted a CFD analysis to understand the hydrodynamics of this new technology for future developments.
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Shafel, Kristin Frances Chen Yi. "My heart reacts." Diss., UMK access, 2008.
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Thesis (M.M.)--Conservatory of Music and Dance. University of Missouri--Kansas City, 2008.For alto saxophone and string quartet. "A thesis in music composition." Advisor: Chen Yi. Typescript. Duration: 15:00. Vita. Title from "catalog record" of the print edition Description based on contents viewed Apr. 14, 2009. Online version of the print edition.
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Grunwald, G., Ulrich Rohde, and Thomas Höhne. "Coolant mixing in pressurized water reactors." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30570.
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For the analysis of boron dilution transients and main steam line break scenarios the modelling of the coolant mixing inside the reactor vessel is important. The reactivity insertion due to overcooling or deboration depends strongly on the coolant temperature and boron concentration. The three-dimensional flow distribution in the downcomer and the lower plenum of PWR's was calculated with a computational fluid dynamics (CFD) code (CFX-4). Calculations were performed for the PWR's of SIEMENS KWU, Westinghouse and VVER-440 / V-230 type. The following important factors were identified: exact representation of the cold leg inlet region (bend radii etc.), extension of the downcomer below the inlet region at the PWR Konvoi, obstruction of the flow by the outlet nozzles penetrating the downcomer, etc. The k- turbulence model was used. Construction elements like perforated plates in the lower plenum have large influence on the velocity field. It is impossible to model all the orifi! ces in the perforated plates. A porous region model was used to simulate perforated plates and the core. The porous medium is added with additional body forces to simulate the pressure drop through perforated plates in the VVER-440. For the PWR Konvoi the whole core was modelled with porous media parameters. The velocity fields of the PWR Konvoi calculated for the case of operation of all four main circulation pumps show a good agreement with experimental results. The CFD-calculation especially confirms the back flow areas below the inlet nozzles. The downcomer flow of the Russian VVER-440 has no recirculation areas under normal operation conditions. By CFD calculations for the downcomer and the lower plenum an analytical mixing model used in the reactor dynamic code DYN3D was verified. The measurements, the analytical model and the CFD-calculations provided very well agreeing results particularly for the inlet region. The difficulties of analytical solutions and the uncertainties of turbulence models for the numerical solutions require additional experiments. Therefore a 1:5 scaled plexiglas model is under construction at RC Rossendorf. The model can be used variably for PWR's of KONVOI- and EPR- types including the primary loops. The measurements of the mixing effects will be performed with modern wire mesh sensors based on conductivity differences and LDA is used to measure the flow conditions.
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Zakova, Jitka. "Advanced fuels for thermal spectrum reactors." Doctoral thesis, KTH, Reaktorfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103085.
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The advanced fuels investigated in this thesis comprise fuels non− conventional in their design/form (TRISO), their composition (high content of plutonium and minor actinides) or their use in a reactor type, in which they have not been used before (e.g. nitride fuel in BWR). These fuels come with a promise of improved characteristics such as safe, high temperature operation, spent fuel transmutation or fuel cycle extension, for which reasons their potentialis worth assessment and investigation. Their possible use also brings about various challenges, out of which some were addressed in this thesis. TRISO particle fuels with their superior retention abilities enable safe, high−temperature operation. Their combination with molten salt in the Advanced High Temperature Reactor (AHTR) concept moreover promises high operating temperature at low pressure, but it requires a careful selection of the cooling salt and the TRISO dimensions to achieve adequate safety characteristic, incl. a negative feedback to voiding. We show that an AHTR cooled with FLiBe may safely operate with both Pu oxide and enriched U oxide fuels. Pu and Minor Actinides (MA) bearing fuels may be used in BWR for transmutation through multirecycling; however, the allowable amounts of Pu and MA are limited due to the degraded feedback to voiding or low reactivity.We showed that the main positive contribution to the void effect in the fuelswith Pu and MA content of around 11 to 15% consist of the decreased thermalcapture probability in Pu-240, Pu-239 and Am-241 and increased fast and resonance fission probability of U-238, Pu239 and Pu-240. The total void worthmoreover increases during multirecycling, limiting the allowable amount ofMA to 2.45% in uranium−based fuels. An alternative, thorium−based fuel allows for 3.45% MA without entering the positive voiding regime at any point of the multirecycling. The increased alpha−heating associated with the use of transmutation fuels, is at level 24−31 W/kgFUEL in the uranium based fuels and 32−37 W/kgFUEL in the thorium−based configurations. The maximum value of the neutron emission, reached in the last cycle, is 1.7·106 n/s/g and 2·106 n/s/g for uranium and for thorium−based fuels, respectively. Replacing the standard UO2 fuel with higher−uranium density UN orUNZrO2 fuels in BWR shows potential for an increase of the in-core fuelresidence time by about 1.4 year. This implies 1.4% higher availability of the plant. With the nitride fuels, the total void worth increases and the efficiency of the control rods and burnable poison deteriorates, but no major neutronics issue has been identified. The use of nitride fuels in the BWR environment is conditioned by their stability in hot steam. Possible methods for stabilizing nitride fuels in water and steam at 300◦ C were suggested in a recent patentapplication.QC 20121004
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Lambert, Paul G. "Gas evolution in batch chemical reactors." Thesis, London South Bank University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618653.
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Potters, Kimberlee. "Magnetic Resonance Imaging of columnar reactors." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336775.
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Ghodasara, Kamlesh kumar. "Synthesis and optimisation of catalytic reactors." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494606.
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Sustainable industrial activity requires that processes should use raw materials as efficiently as is economic and practical to preserve the resources as much as possible. The major source of inefficiency in the use of raw material in most chemical processes is in chemical reactors. This work focuses on developing various design options that allow the raw materials efficiency of chemical reactors to be improved by the simultaneous design of the catalyst and the reactor. Practical consideration such as the deterioration of performance of the catalytic reactor or network of catalytic reactors through time, resulting from catalyst deactivation is considered in this work to make reactor designs more reliable and practical.
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Szanto, Dominic A. "Characterisation of electrochemical filter-press reactors." Thesis, University of Portsmouth, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286086.
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Khor, Jen Nee. "Oxidation of pesticides in photocatalytic reactors." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403398.
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Maciel, Filho Rubens. "Modelling and control of multitubular reactors." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328962.
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Wu, W. S. "Bubble induced mixing in electrochemical reactors." Thesis, University of Southampton, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333212.
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Chung, Kenneth Hoi Kan. "Mixing in high throughput experimentation reactors." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/909/.
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The application of High Throughput Experimentation (HTE) stirred vessels in the catalyst and pharmaceutical industries enable the parallel screening of potential formulations. Such tasks only require a fraction of the raw material and experimental time that are needed in conventional lab scale reactors. However their small sizes (~ 15-250 ml) contribute to a low Reynolds Number, Re, which results in poor mixing efficiencies. Together with unconventional geometries, i.e. lack of baffles and simple impeller designs, their fundamentals are not fully understood. The present study applies Particle Image Velocimetry (2-D PIV) and Planar Laser Induced Fluorescence (PLIF) techniques to a HTE scale stirred vessel (T = 45 mm, V = 72 ml) to determine the mixing behaviour. Three mixing strategies: centreline unbaffled (U), conventional baffled (B) and off-centre eccentric agitator (E) configurations, were investigated using a pitched blade turbine (PBT). Experiments were performed in the high transitional regime (Re \( \approx\) 6000) using distilled water as the working fluid. A uniform power input of P/V = 168Wm\(^{-3}\) was applied. A method based on multiple horizontal and vertical 2-D PIV measurements was used to reconstruct the 3-D flow field in each of these configurations, since the conventional 3-D PIV is unusable at this scale. It was found that the determination of turbulent kinetic energy (TKE) using the isotropic assumption was perfectly valid for (B), but will lead to a considerable underestimation in both (U) and (E). In addition to the three configurations, a square section vessel (S) (T = 41.5 mm, V = 72 ml) and regular vessel with a tilted impeller axis (T) were also studied. With a modified experimental procedure a log variance method for mixing time was applied using PLIF where all the usable pixels in an image were accounted for. Not only was (U) found to be highly inefficient, (B) also registered a slower mixing time due to a small amount of tracer being trapped behind the baffles, which makes the (E), (S) and (T) an even better choice in turbulent mixing. The use of (S) enabled the formation of a more compact HTE unit, also its trailing vortices were able to reach a height of y/H = 0.6, bringing more energy to the upper reaches of vessel, as visualised by angle resolved PIV measurements. The flow number of impeller and the amount of pseudo-turbulence were also determined and they agreed well with literature values. However in the laminar mixing regime using Polypropylene Glycol (PPG) as the Newtonian working fluid (μ = 0.4–0.8 Pa s, P/V = 0.6–5.5 kWm\(^{-3}\), Re = 5–35), at low Re values, (S) only managed a mixing performance comparable to the (U) configuration as the baffling effect of its four corners are less pronounced. However, mixing performance improves in (S) at higher Re values. (B) and (E) gave a comparable mixing performance, suggesting (E) should always be adopted for its viability in both turbulent and laminar mixing regimes. For gas-liquid mixing using air and water (P\(_G\)/V = 168 Wm\(^{-3}\), Q\(_G\) = 0.5–1.0 vvm), an image analysis algorithm was developed which enabled measurement of gas and liquid phase velocities separately. In addition to the PBT, a Rushton Disk Turbine (RDT) was also used (C = D = 0.33T). The power input required for the small mixing vessel to achieve complete gas dispersion was not achievable at the required gas flow rate; hence the experiments are carried out in the flooding regime. This had the advantage of clearly discernible differences between gas and liquid flow pattern for validation purposes. A new image algorithm was written to separate out bubbles in the imaging plane which transforms the in-plane bubbles into tracer particles. The local velocities of the gas phase are then obtained using the conventional cross-correlation technique. The results showed qualitative agreement with experimental observations of global gas phase flow patterns in literature.
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Srinivasan, Ravi 1971. "Microfabricated reactors for partial oxidation reactions." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9865.
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Visosky, Mark Michael. "Actinide minimization using pressurized water reactors." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41276.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2006.Includes bibliographical references (p. 227-232).
Transuranic actinides dominate the long-term radiotoxity in spent LWR fuel. In an open fuel cycle, they impose a long-term burden on geologic repositories. Transmuting these materials in reactor systems is one way to ease the long-term burden on the repository. Examining the maximum possible burning of trans-uranic elements in Combined Non-Fertile and U02 (CONFU) PWR assemblies is evaluated. These assemblies are composed of a mix of standard U02 fuel pins and pins made of recycled trans-uranics (TRU) in an inert matrix, and are designed to fit in current or future PWRs. Applying appropriate limits on the neutronic and thermal safety parameters, a CONFU-Burndown (CONFU-B) assembly design is shown to attain net TRU destruction in each fuel batch through at least 9 recycles. This represents a time span of nearly 100 years of in-core residence and out-of-core storage time. In this way, when the TRU is multi-recycled, only fission products and separation/reprocessing losses are sent to the repository, and the initial inventory of TRU is reduced over time. Thus, LWRs are able to eventually operate in a fuel cycle system with an inventory of transuranic actinides much lower than that accumulated to date. Three recycling strategies are considered, all using a 4.5-year in core irradiation, followed by cooling and reprocessing. The three strategies involve a short-term cooling (6-year) after discharge, a longer-term cooling (16.5-year) after discharge, or a strategy called Remix. The Remix strategy involves partitioning the Pu/Np after 6-year cooling for immediate recycle, and partitioning the Am/Cm for an additional 10.5-year cooling before remixing it into the next CONFU-B batch. At equilibrium, the CONFU-B can burn approximately 1.5 kg to 10.0 kg of TRU per TWhe depending on the recycle strategy used.
(cont.) This represents a net burning rate of 2-8% of the TRU loaded per assembly, in addition to burning an amount equivalent to the TRU produced in the U02 pins. However, the highly heterogeneous nature of these assemblies can result in fairly high intra-assembly pin power peaking. By design, an IMF pin in the assembly carries the highest power to maximize the TRU destruction. For the initial TRU loading, the highest power peaking in an IMF pin is 1.183. This is compensated by having cooler pins in the immediate vicinity. Even so, the pin peaking distribution in the assembly can result in reduced thermal margins. The assembly mentioned above has an MDNBR of 1.43, instead of 1.62 for the all-U02 assembly, based on a core-wide radial peak-to-average assembly power peaking of 1.50. Use of neutron poisons and tailored enrichment schemes reduces the neutronic reactivity of fresh assemblies, while improving MDNBR to 1.51. In addition, RELAP was used to evaluate the fuel behavior under large break LOCA conditions. CONFU-B performance under these conditions was comparable to the standard all-UO2 assembly. Several options for spent fuel recycling in LWRs are compared economically, and all are found to be more costly than making fresh U02 fuel from mined ore. However, the CONFU-B strategy is less costly on a mills/kWhe basis than other thermal recycling strategies that recycle the full TRU vector. Given OECD estimates for the unit costs of each fuel type, and assuming 10% carrying charge factor, this cost is 12.3 mills/kWhe for the CONFU-B recycle, compared to 25.7 mills/kWhe for MOX-UE and 4.9 mills/kWhe for all UO2.
(cont.) Note that these FCCs assume the disposal fee collected during power generation of a previous cycle can be invested while the fuel is cooling and provide a credit to the cycle that uses the fuel after reprocessing. The fuel handling challenges of multirecycling TRU in CONFU-B assemblies are compared to other multi-recycling strategies. If we assume that the spent fuel from, the seventh recycle in each strategy is no longer recyclable and must be sent to the repository in its entirety. the CONFU-B strategy still places much less total burden on the repository than the once-through cycle, and even less burden than the current MOX cycle. Finally, a methodology for calculating the time integrated proliferation risk of a fuel cycle is introduced. An innovation of this methodology is the discounting of future risks to calculate an overall present value risk of a given cycle. Under this methodology, the CONFU-B presents lower risks than other multi-recycling strategies in the first 100 years. For a 10% rate of discount of risk, the CONFU-B risks are comparable to the once-through cycle. The longer term risk favors recycling due to the limited accumnulation of repository risk.
by Mark M. Visosky.
Ph.D.
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Lebenhaft, Julian R. (Julian Robert) 1954. "MCNP4B modeling of pebble-bed reactors." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/28288.
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Thesis (Nucl.E. and S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, February 2002.Includes bibliographical references (v. 1, leaves 152-171).
The applicability of the Monte Carlo code MCNP4B to the neutronic modeling of pebblebed reactors was investigated. A modeling methodology was developed based on an analysis of critical experiments carried out at the HTR-PROTIEUS and ASTRA facilities, and the critical loading of the HTR-10 reactor. A body-centred cubic lattice of spheres with a specified packing fraction approximates the pebble bed, and exclusion zones offset the contribution of partial spheres generated by the geometry routines in MCNP4B at the core boundaries. The coated fuel particles are modeled in detail and are distributed over the fuelled region of the fuel sphere using a simple cubic lattice. This method predicted the critical core loading accurately in all cases. The calculation of control-rod worths in the more decoupled tall annular ASTRA core gave results within 10% compared to the reported experiments. An approximate method was also developed for the MCNP4B modeling of pebble-bed reactors with burnup. The nuclide densities of homogenized layers in the VSOP94 reactor model are transferred to the corresponding MCNP4B model with the lattice of spheres represented explicitly. The method was demonstrated on the PBMR equilibrium core, and used for a parallel study of burnup k- and isotopics on a single pebble. Finally, a study was carried out of the proliferation potential of a modular pebble-bed reactor for both normal and off-normal operation. VSOP94 analysis showed that spent fuel from pebble-bed reactors is proliferation resistant at high discharge burnup, because of its unfavourable plutonium isotopic composition and the need to divert -157,000 pebbles to accumulate sufficient 239Pu for a nuclear weapon. The isotopics of first-pass fuel pebbles are more favourable, but even more pebbles (-258,000) would be needed. However, a supercell MOCUP model was used to demonstrate that -20,000 pebbles would be needed if loaded with depleted uranium. But the associated reactivity loss would necessitate a compensatory increase in core height of approximately 50 cm. Such a change in core loading, as well as the properties of the special pebbles, would be noticed in a safeguarded facility.
by Julian Robert Lebenhaft.
Nucl.E.and S.M.
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Müller, Christoph. "Fundamental studies of fluidised bed reactors." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611954.
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Constantinou, A. "CO2 absorption in microstructured membrane reactors." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1348316/.
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The objective of this work is to study experimentally and theoretically novel multiphase microreactors and characterize them in relation to hydrodynamics and mass transfer, in order to evaluate, understand and improve their performance. In order to achieve this CO2 absorption in sodium hydroxide and amine solutions an example of a fast gas-liquid reaction has been investigated in a single microstructured metallic mesh reactor, CRL reactor, PTFE single channel membrane reactor and the silicon nitride mesh reactor. CO2 absorption in sodium hydroxide solution was initially studied experimentally and theoretically in a metal microstructured mesh reactor. The differential mass balances to describe the concentration profiles of components in the three domains (gas/membrane/liquid), were solved with Comsol Multiphysics (modeling software for finite element analysis of partial differential equations). The model indicated that the carbon dioxide is consumed within few microns from the gas – liquid interface, and the dominant resistance for mass transfer is located in the mesh because it is wetted by the liquid reactant. In order to overcome the limitation of the extra resistance to the mass transfer in the metallic mesh, PTFE membranes were used in the single channel reactor, which are considered as hydrophobic to aqueous solutions of NaOH and amines. Monoethanolamine solution (MEA) absorbed more CO2 than diethanolamine (DEA) since the reaction rate constant for MEA is higher than DEA. 8 channel (PTFE) microreactor showed much higher CO2 removal efficiency than the metallic mesh microreactor. Furthermore the model indicated partial-wetting of the PTFE membrane when NaOH solution was used as an absorbent. In order to enhance mass transfer staggered herringbones were used on the floor of the liquid side of the single channel PTFE microreactor. No enhancement of mass transfer was observed with the use of staggered herringbones. A possible reason for that is that a limit for the fast second-order reaction is reached for enhancement and that the apparent reaction rate is independent from mass transfer for our case, or that the herringbones are far away from the reaction zone and cannot create the appropriate stirring for enhancement. In order to increase throughput, carbon dioxide absorption in sodium hydroxide solution was performed in the metallic mesh ‘scale-out’ reactor (with 4 meshes). CO2 removal efficiency for the ‘scale-out’ reactor was significantly lower than the single mesh reactor, which is probably due to breakthrough of liquid in the gas phase (stagnant liquid) or uneven flow distribution in each plate of the ‘scale-out’ reactor. Finally a silicon nitride mesh reactor developed by Bayer Technology Services and FluXXion was used for CO2 absorption in aqueous solutions of NaOH and DEA. The silicon nitride mesh reactor showed better performance than the PTFE single channel reactor, the metallic 8 channel reactor and the CRL mesh reactor when NaOH was used, due to the very thin membrane of 1 μm thickness, which makes the resistance to mass transfer very small.
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Grunwald, G., Ulrich Rohde, and Thomas Höhne. "Coolant mixing in pressurized water reactors." Forschungszentrum Rossendorf, 1998. https://hzdr.qucosa.de/id/qucosa%3A21884.
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For the analysis of boron dilution transients and main steam line break scenarios the modelling of the coolant mixing inside the reactor vessel is important. The reactivity insertion due to overcooling or deboration depends strongly on the coolant temperature and boron concentration. The three-dimensional flow distribution in the downcomer and the lower plenum of PWR's was calculated with a computational fluid dynamics (CFD) code (CFX-4). Calculations were performed for the PWR's of SIEMENS KWU, Westinghouse and VVER-440 / V-230 type. The following important factors were identified: exact representation of the cold leg inlet region (bend radii etc.), extension of the downcomer below the inlet region at the PWR Konvoi, obstruction of the flow by the outlet nozzles penetrating the downcomer, etc. The k- turbulence model was used. Construction elements like perforated plates in the lower plenum have large influence on the velocity field. It is impossible to model all the orifi! ces in the perforated plates. A porous region model was used to simulate perforated plates and the core. The porous medium is added with additional body forces to simulate the pressure drop through perforated plates in the VVER-440. For the PWR Konvoi the whole core was modelled with porous media parameters. The velocity fields of the PWR Konvoi calculated for the case of operation of all four main circulation pumps show a good agreement with experimental results. The CFD-calculation especially confirms the back flow areas below the inlet nozzles. The downcomer flow of the Russian VVER-440 has no recirculation areas under normal operation conditions. By CFD calculations for the downcomer and the lower plenum an analytical mixing model used in the reactor dynamic code DYN3D was verified. The measurements, the analytical model and the CFD-calculations provided very well agreeing results particularly for the inlet region. The difficulties of analytical solutions and the uncertainties of turbulence models for the numerical solutions require additional experiments. Therefore a 1:5 scaled plexiglas model is under construction at RC Rossendorf. The model can be used variably for PWR's of KONVOI- and EPR- types including the primary loops. The measurements of the mixing effects will be performed with modern wire mesh sensors based on conductivity differences and LDA is used to measure the flow conditions.
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Manier, Hervé. "Contribution au pilotage d'ateliers flexibles reactifs." Besançon, 1995. http://www.theses.fr/1995BESA2009.
Full textAbstract:
Pour faire face a l'evolution du marche de la demande, la problematique generale du pilotage des ateliers flexibles est devenue de plus en plus cruciale pour les entreprises. De nombreuses methodes de conduite sont basees sur la realisation d'un ordonnancement predictif, et sont incapables d'exploiter le potentiel des flexibilites du systeme de production en cas de perturbations. Il est alors indispensable d'introduire un niveau de decision dans l'atelier, afin de pouvoir reagir aux aleas de production. Dans cette etude, nous particularisons le probleme au pilotage d'un atelier base autour d'un systeme de convoyage en anneau. Nous comparons tout d'abord differentes methodes de pilotage, allant de la politique totalement reactive n'ayant recours a aucune forme d'ordonnancement, en passant par une autre utilisant des regles heuristiques pour adapter la production a l'etat reel de l'atelier, jusqu'a la methode appliquant un ordonnancement predictif sans tenir compte des eventuelles perturbations. Forts des resultats comparatifs, obtenus par simulation, sur les performances de ces diverses methodes, nous proposons une nouvelle approche qui essaie de concilier les objectifs de productivite du niveau ordonnancement et les besoins de reactivite du niveau de decision de l'atelier