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The objective of this research was to evaluate the efficiency of a sequential batch reactor operating in the treatment of effluents from an ice cream producer. They implemented two times of 10 and 12 hours, an anaerobic, aerobic and anoxic operational sequence, and a cell retention time of 25 days. The physicochemical parameters measured were chemical total oxygen demand, ammoniacal nitrogen, nitrites, nitrates, orthophosphates, total phosphorus, pH and total alkalinity at the beginning, end of each phase and outlet of the reactor for each treatment evaluated. According to the results obtained, the percentages of COD removal were between 89.8 and 94.6% for 10 and 12 h, respectively, without statistically significant differences between the applied times. The SBR was efficient for the removal of the nutrients present in the industrial effluent, reaching a maximum removal of total nitrogen of 81.0% and total phosphorus of 51.0%., El objetivo de esta investigación fue evaluar la eficiencia de un reactor por carga secuencial operado en el tratamiento de efluentes de una productora de helados. Se implementaron dos tiempos de 10 y 12 horas, una secuencia operacional anaerobia, aerobia y anóxica, y un tiempo de retención celular de 25 días. Los parámetros fisicoquímicos medidos fueron la demanda química de oxígeno total, nitrógeno amoniacal, nitritos (NO2-), nitratos, ortofosfatos, fósforo total, pH y alcalinidad total al inicio, final de cada fase y salida del reactor para cada tratamiento evaluado. De acuerdo a los resultados obtenidos, los porcentajes de remoción de DQOT estuvieron entre 89,8 y 94,6% para 10 y 12 h, respectivamente, sin diferencias estadísticamente significativas entre los tiempos aplicados. El SBR fue eficiente para la remoción de los nutrientes presentes en el efluente industrial, alcanzando una remoción máxima de nitrógeno total de 81,0% y de fósforo total de 51,0%.

According to the world Summit of sustainable Development, the major reason for lack of safe water is either scarcity of water or contamination of water sources. Therefore this study eye on developing nations, seeks to find sustainable, yet economically and socially practical solution to the problems associated with polluted water. To fulfil the objectives of the present study, two medicinal value plants Dhav (Anogeissuslatifolia wall.) and Aragvadha (Cassia fistula Linn.) were selected and absorbents were prepared from the bark of both the plants. Then the reactors were prepared using the different compositions of sand, gravel, absorbents of Dhavand Aragvadha and cotton.In this way four filter reactors were prepared. The feeding rate of raw water is maintained at 0.5 litre per hour. The results revealed that Dhav plant absorbent was found more effective thanAragvadha. All reactors shows different efficiencies for different parameters suggesting that reactors should be prepared based on need or targeted parameters. Over all reactor 4 shows better efficiency for all the parameters. The main exclusivity of the present reactor is low cost with no electricity demand. The prepared reactors are environment friendly and easily implementable but further study is required to prove it on large scale.

The use of a real-time operating system (RTOS) raises the abstraction level for embedded systems design when compared to traditional bare-metal programming, resulting in simpler and more reusable application code. Modern RTOSes for resource-constrained platforms, like Zephyr and FreeRTOS, also offer threading support, but this kind of shared memory concurrency is a poor fit for expressing the reactive and interactive behaviors that are common in embedded systems. To address this, alternative concurrency models like the actor model or communicating sequential processes have been proposed. While those alternatives enable reactive design patterns, they fail to deliver determinism and do not address timing. This makes it difficult to verify that implemented behavior is as intended and impossible to specify timing constraints in a portable way. This makes it hard to create reusable library components out of common embedded design patterns, forcing developers to keep reinventing the wheel for each application and each platform. In this paper, we introduce the embedded target of Lingua Franca (LF) as a means to move beyond the threaded programming model provided by RTOSes and improve the state of the art in embedded programming. LF is based on the reactor model of computation, which is reactive, deterministic, and timed, providing a means to express concurrency and timing in a platform-independent way. We compare the performance of LF versus threaded C code - both running on Zephyr - in terms of response time, timing precision, throughput, and memory footprint.

Pt-supported catalysts are widely used industrially for hydrogenation reactions. However, the kinetics of hydrogen activation, a critical step for any hydrogenation reaction, is still not well understood on supported Pt surfaces. Recent studies had shown that activity and selectivity vary with Pt nuclearity for the acetylene semihydrogenation reaction, increasing in activity and decreasing in selectivity while increasing the particle size from single atoms (SA) to sub-nanoclusters to nanoparticles (NP), attributing the cause of these differences on activities to the activity of H2 activation in the H/D isotopic exchange reaction. In this work, the kinetics of H2 is studied by performing the H2-D2 isotopic exchange reaction on Pt-supported catalysts with different nuclearity to extract the activation barriers and pre-exponential factors for dissociating adsorption and associative desorption (Eads, Edes, and vads, vdes respectively) from the microkinetic model derived from the Bonhoeffer Farkas mechanism, this to perform a more in-depth analysis regarding the differences in activity when comparing the H2 adsorption energy (Eads+ = Eads-Edes) and frequency factors as a function of nuclearity. Experiments were carried out in a quartz tubular fixed bed reactor coupled with a Mass Spectrometer to analyze the product gas by carrying out both, an integral analysis (from 0 to equilibrium conversion) by performing light-off experiments and differential analysis (low conversions) by performing Arrhenius experiments in the low and high coverage regions.

En esta memoria se ha realizado un análisis de los reactores de generación IV llamados molten salt reactors, con la finalidad de ver si estos reactores podrían ser una opción válida para reducir las emisiones gei en el sector naval, siendo implementados como sistemas de propulsión de los buques de mayor tamaño. Para realizar este estudio se han realizado estudios y comparativas entre este tipo de reactores y otros sistemas de generación de energía, en base a diferentes parámetros como: las huella ecológica generada, emisiones operacionales, potencias entregadas y costes económicos. El estudio de estos factores se ha considerado básico para poder llegar a conclusiones sobre el objetivo inicial previsto. las herramientas utilizadas para desarrollar este trabajo han sido las siguientes: herramientas ofimáticas (hojas de cálculo, editores de texto...), Web grafías, bibliografías y documentos específicos suministrados por empresas. como conclusiones básicas de la posible implementación de un msr como sistema de propulsión, en base a la situación actual del sector naval, se resumen en: 1.Los MSR generan menor cantidad de emisiones que los sistemas de propulsión convencionales. 2. Menor coste económico a largo plazo comparado (20 años de operación) con otros sistemas de propulsión actuales. 3. Posible viabilidad de implementación en el sector a medio y largo plazo. En esta memoria se ha realizado un análisis de los reactores de generación iv llamados molten salt reactors, con la finalidad de ver si estos reactores podrían ser una opción válida para reducir las emisiones gei en el sector naval, siendo implementados como sistemas de propulsión de los buques de mayor tamaño. para realizar este estudio se han realizado estudios y comparativas entre este tipo de reactores y otros sistemas de generación de energía, en base a diferentes parámetros como: las huella ecológica generada, emisiones operacionales, potencias entregadas y costes económicos. El estudio de estos factores s, Objectius de Desenvolupament Sostenible::14 - Vida Submarina, Objectius de Desenvolupament Sostenible::13 - Acció per al Clima

The significant loads of organic matter and nitrogen in the wastewater of educational institutions have led to the search for efficient, economical, easy-to-operate purification systems that allow wastewater to be considered as a resource that can be evaluated and treated so that its discharge to the natural environment does not have a high impact on water sources and generates alterations to aquatic ecosystems. Artificial wetlands are promising treatment systems that work by bio filtration, allowing the elimination of organic loads and generating discharges that can be used in activities that do not involve the use of drinking water (Metropolitan Area of the Aburrá Valley, 2015). The coupling to these systems, of reactors with algae, becomes a viable option. For the removal of nitrogen and organic matter that come from wetlands, in order to continue the degradation process, because micro algae capture inorganic nutrients that are used to produce biomass, while reducing the capacity of Effluent to cause eutrophication in water bodies (Candela, 2016). This project will present the results of the evaluation of the removal of nitrogen and organic matter through a system of artificial wetlands with horizontal subsurface flow, planted with Heliconia psittacorum and coupled to fixed-bed reactors with algae, inoculated with Chlorella strains vulgaris, where it is expected to find a high efficiency in the degradation of nitrogen in a percentage of 73,4%, organic matter between 30-40%, total coliforms of 87% and fecal coliforms (E. coli) of 88%., Las importantes cargas de materia orgánica y nitrógeno en las aguas residuales de instituciones educativas, han llevado a la búsqueda de sistemas de depuración eficientes, económicos, fáciles de operar y que permitan considerar el agua residual como un recurso que se pueda evaluar y tratar para que su descarga a fuentes hídricas naturales no tenga un alto impacto y genere alteraciones a los ecosistemas acuáticos. Los humedales artificiales son sistemas de tratamiento promisorios que trabajan por biofiltración, en estos se dan procesos físicos, químicos y microbiológicos que permiten la eliminación de materia orgánica, bioindicadores de contaminación fecal y turbidez del agua residual, permitiendo que esta sea utilizada en actividades que no impliquen el uso de agua potable (Área Metropolitana del Valle de Aburrá, 2015). Los humedales artificiales de flujo subsuperficial acoplados a reactores de lecho fijo con microalgas, se convierte en una opción promisoria para la remoción de nitrógeno y materia orgánica procedente del efluente tratado en los humedales, con el fin de continuar el proceso de degradación, debido a que las microalgas captan nutrientes inorgánicos que se aprovechan para producir biomasa, y a la vez, se reduce la capacidad del efluente de provocar eutrofización en los cuerpos de agua (Candela, 2016). En este proyecto se presentan los resultados de la evaluación de la remoción de nitrógeno y materia orgánica a través de un sistema de humedales artificiales de flujo subsuperficial horizontal, plantados con Heliconia psittacorum y acoplados a reactores de lecho fijo con microalgas, inoculados con cepas de Chlorella vulgaris, donde se encontró una eficiencia en la transformación de nitrógeno de 73,4%, materia orgánica entre el 30-40%, coliformes totales del 87% y coliformes fecales (E.coli) del 88%.

L'objectiu d'aquest treball es dissenyar un reactor per a la descomposició d'amoníac en hidrogen i nitrogen, fent us de un material catalitzador. L'anterior per alimentar amb hidrogen una cel·la de combustible de 150 W. Addicionalment, es considera la fabricació de la malla catalitica dissenyada (part interna que esta en contacte amb fluid, on succeeix la reacció) mitjançant la impressió 3D. El material catalític considerat és Ni-Ru / CeO2 amb un 2.5% de níquel i un 0.5% de ruteni i la taxa de reacció utilitzada ésta determinada per Lucentini, García Colli, et al. (2021). El disseny, la modelació i la simulació numèrica dels reactors catalític han estat realitzades mitjançant el software COMSOL Multiphysics®. En la primera secció de l'estudi, es simula el reactor amb diferents paràmetres geomètrics, per a determinar el seu efecte en el conjunt. A la segona part, es dissenya el reactor òptim, d'acord amb la geometria definida i s’analitzar la mecànica de fluids, transferència de massa, i de calor. A l'última secció es realitza una exploració de configuracions geomètriques alternatives per a comparar el rendiment dels reactors. El disseny òptim és un reactor de 30 mm de diàmetre i 15 mm de longitud, el qual és capaç de convertir un flux d'amoníac de 53.15 g / h completament . A més, el reactor ha d'operar a una temperatura de 600 °C a la paret i el flux d’entrada ha de ser pre-escalfat a 500 °C., El objetivo de este trabajo corresponde al diseño de un reactor para la descomposición de amoniaco en hidrógeno y nitrógeno, utilizando un material catalizador. Lo anterior para alimentar con hidrogeno una celda de combustible de 150 W. Adicionalmente, el diseño de la malla catalítica (parte interna en contacto con fluido, donde la reacción sucede) considera su manufactura mediante impresión 3D. El material catalítico considerado es Ni-Ru/CeO2 con 2.5% de níquel y 0.5% de rutenio y la tasa de reacción utilizada es la determina por Lucentini, García Colli, et al. (2021). Han sido realizados el diseño, modelación y simulación numérica de reactores catalíticos usando COMSOL Multiphysics®. En la primera sección del estudio, reactores con diferentes parámetros geométricos fueron simulados, para determinar su efecto en el desempeño del reactor. En la segunda parte, se diseñó el reactor óptimo de acuerdo con la geometría definida y se analizó la mecánica de fluidos, transferencia de masa y calor. En la última sección se realizó una exploración de otras configuraciones geométricas para comparar el rendimiento de los reactores. El diseño optimo es un rector de 30 mm de diámetro y un largo de 15 mm, el cual es capaz de convertir totalmente un flujo de amoniaco de 53.15 g/h. Además, el reactor debe operar a una temperatura de pared de 600°C y el flujo entrante debe ser precalentado a 500°C., The objective of this work corresponds to the design of a catalytic reactor for ammonia decomposition into hydrogen and nitrogen, using a catalyst material. This for feed with hydrogen a fuel cell of 150W. Additionally, the design of the catalytic grid (internal part in touch with the fluid, where the reaction occurs) considers it manufacturing using 3D printing technology. The catalytic material considered is Ni-Ru/CeO2 with 2.5% of nickel and 0.5% of ruthenium and the reaction rate utilized is the one determined by Lucentini, García Colli, et al. (2021). Have been done the design, modelling and numerical simulation of catalytic reactors using COMSOL Multiphysics®. In the first part of the study, reactors with different geometrical parameters were simulated, to determine its effect on the reactor performance. In the second part, a optimal reactor was design according to the geometry defined and its fluid mechanics, heat and mass transfers. In the last section, an exploration of others geometrical configurations was done to compare the performance of the reactors. The optimal design is a 30 mm diameter reactor and a length of 15 mm, which can totally convert an ammonia flow of 53.15 g/h. Besides, the reactor must operate at 600°C at the wall and the entering flow must be pre-heated at 500°C.

Actors have become widespread in programming languages and programming frameworks focused on parallel and distributed computing. While actors provide a more disciplined model for concurrency than threads, their interactions, if not constrained, admit nondeterminism. As a consequence, actor programs may exhibit unintended behaviors and are less amenable to rigorous testing. The same problem exists in other dominant concurrency models, such as threads, shared-memory models, publish-subscribe systems, and service-oriented architectures.We propose “reactors,” a new model of computation that combines synchronous-reactive principles with a sophisticated model of time to enable determinism while preserving much of the style and performance of actors. Reactors promote modularity and allow for distributed execution. The relationship that reactors establish between events across timelines allows for: 1. the construction of programs that react predictably to unpredictable external events; 2. the formulation of deadlines that grant control over timing; and 3. the preservation of a deterministic distributed execution semantics under quantifiable assumptions. We bring the deterministic concurrency and time-based semantics of reactors to the world of mainstream programming languages through Lingua Franca (LF), a polyglot coordination language with support (so far) for C, C++, Python, and TypeScript. In LF, program logic is given in one or more of those target languages, enabling developers to use familiar languages and integrate extensive libraries and legacy code. The main contributions of this work consist of a formalization of reactors, the implementation of an efficient runtime system for the execution of reactors, and the design and implementation of LF.

Power or Energy is an important part of the human modern daily life. It is the lifeline of any modern civilization. In all areas of man’s modern life, energy is an integral part of the social community and society lives hand in hand with the essential existence of energy as a vital part of every mankind here in this modern planet. In the development of electricity as a source of energy, many forms of technology have evolved from the use of coal to power steam engines and the use of crude oil as a fuel to power modern engines and the use of nuclear energy to power nations and of course the development of renewable forms of energy such as the solar power energy, wind power energy, ocean current energy, water energy from the dams and many other forms of renewable forms of energy. One of these energy that human can harness is the energy which is abundant here on earth, is water and the energy of the sun. If the energy of the sun can be used to harvest the hydrogen and oxygen gas from water then humanity would have an unlimited power and energy for the future to come and mankind would and can help the planet earth restore into to its original state of a minimally polluted atmosphere and reduce the unprecedented natural calamities the world is facing due to global climate change.  This paper highlights the fundamental principles of how this theory can be achieved and the procedures, methods, studies, experiments and research that have been examined in order to achieve what the researchers intend to accomplish as mentioned above which is the development of an energy of the future. This paper is a study on renewable forms of energy and renewable forms of energy is a new, milestone for science as science endeavors to create a sustainable and clean form of energy.

This artefact provides runnable versions of the code samples given in the main publication. An interpreter for the Stella language is provided together with a basic web-based IDE (syntax highlighting + running programs) which is able to run all Stella code given in the main publication. Also included are runnable implementations of the running example from the main publication (a simple wind turbine simulator) implemented in Stella and 6 other languages and frameworks (Akka, Flapjax, FrTime, ReactJS, REScala, and RxJS). While we do not discuss how these other technologies work, we highlight the interesting parts of the implementations of the running example: the difficulties we had, and any particular points of interest related to the claims made in the main publication.

Reactive programming is a programming paradigm whereby programs are internally represented by a dependency graph, which is used to automatically (re)compute parts of a program whenever its input changes. In practice reactive programming can only be used for some parts of an application: a reactive program is usually embedded in an application that is still written in ordinary imperative languages such as JavaScript or Scala. In this paper we investigate this embedding and we distill "the awkward squad for reactive programming" as 3 concerns that are essential for real-world software development, but that do not fit within reactive programming. They are related to long lasting computations, side-effects, and the coordination between imperative and reactive code. To solve these issues we design a new programming model called the Actor-Reactor Model in which programs are split up in a number of actors and reactors. Actors and reactors enforce a strict separation of imperative and reactive code, and they can be composed via a number of composition operators that make use of data streams. We demonstrate the model via our own implementation in a language called Stella.

Пояснювальна записка: 122 сторінки, 36 рисунків, 20 таблиць, 6 додатків, 32 джерела за переліком посилань. Об’єкт дослідження – гетерогенно-каталітичний процес отримання вуглеводневого палива з синтез газу по схемі Фішера-Тропша, суспензійний реактор Фішера-Тропша. Ціль роботи – розроблення програмного забезпечення для обчислення параметрів суспензійного реактора Фішера-Тропша, розроблення програмного забезпечення для обчислення керуючого виливу регулятора температури. Методи дослідження – математична модель реактора, математична модель регулятора. Результатом даної роботи є програмне забезпечення, яке можна використовувати для обрахунку параметрів суспензійного реактора за схемою Фішера-Тропша при заданих умовах та розрахунку керуючого сигналу регулятора для температури при заданих умовах. Актуальність роботи – на сьогоднішній день дивлячись на тенденцію пошуку альтернативних джерел енергії та палива, дуже важливо мати програмне забезпечення, яке б дозволяло змоделювати внутрішні процеси, параметри тиску та температури, вихід продуктів всередині реактора. Крім того, визначивши вплив даних параметрів на систему вцілому, можна керувати цими параметрами для забезпечення максимального виходу цільових продуктів, що дозволить автоматизувати процес зменшивши вплив людського фактору., Explanatory note: 122 pages, 36 figures, 20 tables, 6 appendices, 32 sources in the list of links. The object of study is a heterogeneous-catalytic process for the production of hydrocarbon fuels from gas synthesis by the Fischer-Tropsch scheme, the Fischer-Tropsch suspension reactor. The purpose of the work is to develop software to calculate the parameters of the Fischer-Tropsch suspension reactor, to develop software to calculate the control leakage of the temperature controller. Research methods - mathematical model of the reactor, mathematical model of the regulator. The result of this work is software that can be used to calculate the parameters of a suspension reactor according to the Fischer-Tropsch scheme under specified conditions and to calculate the control signal of the controller for temperature under specified conditions. The urgency of the work - today, despite the tendency to look for alternative sources of energy and fuel, it is very important to have software that would allow to simulate internal processes, pressure and temperature parameters, output of products inside the reactor. In addition, by determining the effect of these parameters on the system as a whole, you can control these parameters to maximize the yield of the target products, which will automate the process by reducing the impact of human factors., Пояснительная записка: 122 страницы, 36 рисунков, 20 таблиц, 6 приложений, 32 источника по перечню ссылок. Объект исследования - гетерогенно-каталитический процесс получения углеводородного топлива из синтез газа по схеме Фишера-Тропша, суспензионный реактор Фишера-Тропша. Цель работы - разработка программного обеспечения для вычисления параметров суспензионного реактора Фишера-Тропша, разработка программного обеспечения для вычисления управляющего утечки регулятора температуры. Методы исследования - математическая модель реактора, математическая модель регулятора. Результатом данной работы является программное обеспечение, которое можно использовать для расчета параметров суспензионного реактора по схеме Фишера-Тропша при заданных условиях и расчета управляющего сигнала регулятора для температуры при заданных условиях. Актуальность работы - на сегодняшний день несмотря на тенденцию поиска альтернативных источников энергии и топлива, очень важно иметь программное обеспечение, которое бы позволяло смоделировать внутренние процессы, параметры давления и температуры, выход продуктов внутри реактора. Кроме того, определив влияние данных параметров на систему в целом, можно управлять этими параметрами для обеспечения максимального выхода целевых продуктов, что позволит автоматизировать процесс уменьшив влияние человеческого фактора.

[ES] Una de las mayores problemáticas ambientales actual y a nivel mundial es la contaminación de las aguas, el problema va más allá de la sola presencia de contaminantes, si no que algunos de ellos provocan daños irremediables en la cadena trófica y a los demás subsistemas ambientales. Uno de los principales problemas es el causado por los vertidos industriales, contaminación que se puede atenuar gracias a los tratamientos de agua y a la mejora de la ciencia y la investigación. El objetivo principal de esta investigación consiste en evaluar la formación de biomasa granular en dos reactores anaerobios (RAFA y RALF) alimentados de manera intermitente con agua residual contaminada con disolventes orgánicos en presencia del polímero Chitosán, así como comprobar la actividad metanogénica del fango formado., [CA] Una de les majors problemàtiques ambientals actual i a nivell mundial és la contaminació de les aigües, el problema va més enllà de la sola presència de contaminants, si no que alguns d'ells provoquen danys irremeiables en la cadena tròfica i als altres subsistemes ambientals. Un dels principals problemes és el causat pels abocaments industrials, contaminació que es pot atenuar gràcies als tractaments d'aigua i a la millora de la ciència i la investigació. L'objectiu principal d'esta investigació consistix a avaluar la formació de biomassa granular en dos reactors anaerobis (RAFA i RALF) alimentats de manera intermitent amb aigua residual contaminada amb dissolvents orgànics en presència del polímer Chitosán, així com comprovar l'activitat metanogénica del fang format., [EN] One of the biggest environmental problems today and worldwide is water pollution, the problem goes beyond the mere presence of pollutants, if not that some of them cause irreparable damage to the trophic chain and other environmental subsystems. One of the main problems is that caused by industrial discharges, pollution that can be attenuated thanks to water treatment and improved science and research. The main objective of this research is to evaluate the formation of granular biomass in two anaerobic reactors (RAFA and RALF) fed intermittently with waste water contaminated with organic solvents in the presence of the Chitosan polymer, as well as to check the methanogenic activity of the sludge formed.

This paper investigates the oxidative dehydrogenation of ethane to produce ethylene at low temperatures (500 degrees C) in metallic structured substrates. To check this point, the FeCrAlloy (R) monoliths with different channel sizes (289-2360 cpsi) were prepared. The monoliths were coated with a Ni/Al2O3 catalyst (by washcoating of alumina and the latter nickel impregnation) and characterized by Scanning Electron Microscopy and Energy-Dispersive X-ray analysis (SEM-EDX), Temperature-Programmed Reduction (TPR), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The catalytic results showed that all monoliths coated with similar to 300 mg of catalyst presented similar ethane conversion (15%) at 450 degrees C. However, the lowest selectivity to ethylene was found for the monolith with the lower channel size and the higher geometric surface area, where a heterogeneous catalyst layer with Ni enriched islands was generated. Therefore, it can be said that the selectivity to ethylene is linked to the distribution of Ni species on the support (alumina). Nevertheless, in all cases the selectivity was high (above 70%). On the other hand, the stability in reaction tests of one of the coated monoliths was done. This structured catalyst proved to be more stable under reaction conditions than the powder catalyst, with an initial slight drop in the first 8 h but after that, constant activity for the 152 h left.

This work studies Ni-based catalyst deactivation and regeneration processes in the presence of H2S under a biogas tri-reforming process for hydrogen production, which is an energy vector of great interest. 25 ppm of hydrogen sulfide were continuously added to the system in order to provoke an observable catalyst deactivation, and once fully deactivated two different regeneration processes were studied: a self-regeneration and a regeneration by low temperature oxidation. For that purpose, several Ni-based catalysts and a bimetallic Rh-Ni catalyst supported on alumina modified with CeO2 and ZrO2 were used as well as a commercial Katalco 57-5 for comparison purposes. Ni/Ce-Al2O3 and Ni/Ce-Zr-Al2O3 catalysts almost recovered their initial activity. For these catalysts, after the regeneration under oxidative conditions at low temperature, the CO2 conversions achieved79.5% and 86.9%, respectivelywere significantly higher than the ones obtained before sulfur poisoning66.7% and 45.2%, respectively. This effect could be attributed to the support modification with CeO2 and the higher selectivity achieved for the Reverse Water-Gas-Shift (rWGS) reaction after catalysts deactivation. As expected, the bimetallic Rh-Ni/Ce-Al2O3 catalyst showed higher resistance to deactivation and its sulfur poisoning seems to be reversible. In the case of the commercial and Ni/Zr-Al2O3 catalysts, they did not recover their activity.

The effects of transmutation produced helium and hydrogen must be included in ion irradiation experiments to emulate the microstructure of reactor irradiated materials. Descriptions of the criteria and systems necessary for multiple ion beam irradiation are presented and validated experimentally. A calculation methodology was developed to quantify the spatial distribution, implantation depth and amount of energy-degraded and implanted light ions when using a thin foil rotating energy degrader during multi-ion beam irradiation. A dual ion implantation using 1.34 MeV Fe+ ions and energy-degraded D+ ions was conducted on single crystal silicon to benchmark the dosimetry used for multi-ion beam irradiations. Secondary Ion Mass Spectroscopy (SIMS) analysis showed good agreement with calculations of the peak implantation depth and the total amount of iron and deuterium implanted. The results establish the capability to quantify the ion fluence from both heavy ion beams and energy-degraded light ion beams for the purpose of using multi-ion beam irradiations to emulate reactor irradiated microstructures.

This work develops a computational fluid dynamics (CFD) framework for high-fidelity modelingof steam methane reforming reactors and furnaces. Initially, a CFD model for a steammethane reforming reactor is developed and its results are shown to closely match industrialplant data. Subsequently, CFD models of steam methane reforming furnaces are developedfor both pilot-scale and full industrial scale furnaces. These furnace CFD models capture thephysical dimension, transport phenomena, and core components of a reformer utilized in anindustrial plant. Comparison of the CFD models with industrial plant data demonstrates thatmodel predictions are within 1% of industrial measurements for consistent reformer conditions.Finally, to automate the use of the CFD models for reformer furnace balancing, wedevelop a workflow for reformer simulation on the Smart Manufacturing platform. The workflowis designed to be executed without the need of an expert user, to be deployed in a cloudenvironment and to be fully or partially used.

The current understanding of the transport phenomena involved in the operation of industrial fermenters is not sufficient. This is reflected by the limitations seen in their design and operation. A better insight in the local processes taking place (hydrodynamics, gas dispersion, mixing, microbial kinetics) is required to be able to make a step change in the design of those reactors. At the scale of industrially relevant fermenters, experimental methods become quickly limited when detailed information is needed. It was the aim of this research to provide a framework where such information could be gained by means of Computational Fluid Dynamics (CFD) simulations with a manageable computational burden so that it could readily be used by the industrial practitioners. The main focus of this thesis is on the hydrodynamics of bubbly flows in stirred reactors, although, scalar mixing and substrate uptake kinetics studies were also conducted. Because the literature on the standard configured lab/pilot scale single-impeller reactors is vast and the experimental data is abundant, we chose to start with such a system first and, with the learnings gained, moved ultimately to realistic industrial scale multi-impeller fermenters. We also limited ourselves to Rushton type radial pumping disk turbine systems, again on the basis of available data for validation, and also due to time limitations., ChemE/Transport Phenomena

Small-scale parallel trickle-bed reactors were used to evaluate the performance of a commercial hydrodesulfurization catalyst under industrially relevant conditions. Catalyst extrudates were loaded as a single string in reactor tubes. It is demonstrated that product sulfur levels and densities obtained with the single-pellet-string reactor are close to the results obtained in a bench-scale fixed-bed reactor operated under the same conditions. Moreover, parallel single-pellet-string reactors show high reproducibility. To study the hydrodynamic effects of the catalyst-bed packing, the catalyst-bed length was varied by loading different amounts of catalysts, and crushed catalyst was also loaded., ChemE/Catalysis Engineering

Predmet istraživanja ove doktorske disertacije je optimizacija konstruktivnih parametara energetskih niskofrekventnih prigušnica. Predložen je novi metod proračuna veličine i broja vazdušnih procepa, dat je novi algoritam toka proračuna optimizovanih konstruktivnih parametara prigušnica sa jezgrom. Ova tematika svakako pripada aktuelnoj i značajnoj oblasti elektroenergetike, o čemu svedoče brojne međunarodne publikacije. Poslednjih godina, ova problematika dobija novi zamah usled sve većih zahteva za minijaturizacijom elemenata i sklopova koji predstavljaju sastavni deo elektromotornih pogona i postrojenja. Prigušnice u elektrotehnici imaju veliku primenu u svim sistemima gde su potrebne velike snage i mali gubici. Cilj ove disertacije je konstrukcija prigušnica sa jezgrom, koja u mnogome ima dosta zajedničkog sa transformatorima, tako da se sve optimizacione metode razvijenih za transformatore mogu primeniti u oba slučaja. Optimizacija parametara prigušnica sa jezgrom podrazumeva pronalaženje optimalnih konstruktivnih parametara za poznate vrednosti parametara induktivnosti, struje, radne frekvencije i porasta temperature. U prilog ovome, mnoge primene zahtevaju striktna ograničenja u radnoj frekvenciji i snazi pretvarača, čineći dizajn i konstrukciju prigušnica teškim zadatkom. U prvobitnom razvijenim tehnikama proračuna parametara prigušnice koristio se pristup „proizvoda površina“, čiji glavni nedostatak leži u činjenici da je zanemarena funkcionalna zavisnost gustina fluksa i struje od veličine magnetnog kola. Kasnije je ova metoda korigovana i unapređena uvođenjem zavisnosti između snage i gustine fluksa prema dimenzijama jezgra. Druge metode koriste iterativne postupke koji zahtevaju kombinovanje gustina fluksa i struje, i čineći time model najmanjih gubitaka. Neka istraživanja u tu svrhu koriste metode optimizacije putem „veštačke“ inteligencije..., The scope of the research presented in this doctoral dissertation is optimization of construction parameters of low frequency reactors. A new method for calculation of number of air-gaps and number of gaps is proposed, also with new algorithm for construction parameters optimization of power reactors. This t o p i c cert ai n l y belongs t o t h e p o p u l a r and significant field of power engineering, as confirmed by numerous publications. In recent years, this topic has gained attention due to more demanding requirements regarding miniaturization of components and assemblies which are an integral part of electric drives and systems. Reactors in electrical engineering have been used in all systems where needed high power and small losses. Construction of iron-core inductor has a lot of common with transformer construction, so all optimization methods developed for transformers, could be used in both cases. Iron-core inductor design optimization implies that optimal construction parameters should be found for the known values of induction, current, working frequency and temperature increase. In addition to this, many applications require strict limitations and together with requirements in working frequency and converters’ power increasing, make inductors’ design a considerably difficult task. In early designs, the “area product” method had been utilized, wherein the main disadvantage of this method is in the fact that dependence of current and flux densities on the core size are ignored. Later, this method’s was corrected by relating quantitatively the power and flux densities to the core size. Other methods use the iterative procedure that requires the combination o f current and flux densities, which create the smallest losses in the inductor, and certain researchers use the artificial intelligence techniques...

In this paper, the temperature of a pilot-scale batch reaction system is modeled towards the design of a controller based on the explicit model predictive control (EMPC) strategy -- Some mathematical models are developed from experimental data to describe the system behavior -- The simplest, yet reliable, model obtained is a (1,1,1)-order ARX polynomial model for which the mentioned EMPC controller has been designed -- The resultant controller has a reduced mathematical complexity and, according to the successful results obtained in simulations, will be used directly on the real control system in a next stage of the entire experimental framework

El estudio se centra en el problema mecánico del flujo oscilatorio, sin abordar el problema térmico. El Proyecto se articula en dos bloques: - En el primer bloque, se realizara una búsqueda del modelo adecuado para nuestro problema físico - En el segundo bloque, una vez encontrado el modelo que más se ajusta a nuestro caso se procederá a realizar las simulaciones para distintas cantidades de agua y para distintas velocidades para ver como de bueno es el proceso de mezclado con fases inmiscibles

El objetivo general del Proyecto Final de Carrera es desarrollar una simulación numérica que permita estudiar el proceso de mezclado en un reactor de flujo oscilatorio (Oscillatory Baffled Reactor, OBR), sin necesidad de desarrollar un prototipo y probarlo en banco de ensayos. El estudio se centra en el problema fluido-mecánico del flujo oscilatorio, sin abordar el problema térmico. La metodología de simulación consistirá en: • Desarrollo y mallado de las geometrías a simular con Gambit. Se desarrollarán diversas geometrías. • Estudio sobre el método de inyección de especies y definición de las condiciones de contorno y propiedades de los fluidos. • Implementación en Fluent de cada caso. • Análisis de resultados.

This chapter delineats the rationale of combining the membrane and bioreactor technologies and systematically introduces the membrane biological reactors that are the focus of this book. This is followed by a brief account of the history of the various applications of membranes in conjunction with bioreactors and how the initial formats led to the development of the present day commercialized ones. The relative advantages of membrane biological reactors over the conventional biological processes are presented. The current status of the MBR market is described and the drivers propelling its growth along with the constraints are highlighted. The trends in world-wide MBR research is succinctly presented in order to assess whether academic research has so far been able to maintain close relationship with the specific requirements in the industry.

There's a big demand for activated carbon in Ghana, it's used for the country's mining industry as well as in a multitude of other applications. Currently all activated carbon is imported despite the fact that the country has a large supply of agricultural waste that could be used for its production. This study focuses on activated carbon production from oil palm kernel shells from the nations palm oil industry. Earlier research points to a set of specific conditions needed for the production. The pyrolysis process produces biochar from the biomass and the process is set to take place for 2 h at 600 °C after a initial heating of 10 °C/min. The activation process then produces the activated carbon from the biochar and is set to take place for 2 h at 850 °C with a heating rate of 11.6 °C/min. Two reactors are designed to meet the desired conditions. The reactors are both set up to use secondary gases from diesel burners to heat the biomass. The heating is accomplished by leading the hot gases in an enclosure around a rotating steel drum that holds the biomass. To improve the ability to control the temperature profile in the biomass two outlet pipes are set up on top of the reactor, one above the biomass inlet and one above the biomass outlet. By controlling how much gas that flows to each outlet both the heating rate and the stability of the temperature profile can be controlled. The secondary gas inlet is set up facing downwards at the transition between the heating zone (area of initial heating) and the maintaining zone (area of constant temperature). The two reactors are modeled the physics simulation software COMSOL Multiphysics. Reference operating parameters are established and these parameters, as well as parts of the design, are then changed to evaluate how the temperature profile in the biomass and biochar can be controlled. A goal area was set up for the profile in the biomass where it was required to maintain a temperature of between 571.5 and 628.5 °C aft, Det finns en stor efterfrågan på aktivt kol i Ghana, det används dels i landets gruvnäring men även för en mängd andra applikationer. Idag importeras allt aktivt kol, trots att landet har stora mängder restprodukter från jordbruk som skulle kunna användas för produktion av aktivt kol. Det här arbetet fokuserar på produktion av aktivt kol från oiljepalmskärnor från landets palmoljeindustri. Tidigare forskning påvisar en mängd specifika förhållanden som krävs för produktionen. Pyrolysprocessen producerar biokol från biomassa och som mål för processen sätts att den ska hålla 600 °C i två timmar efter en uppvärmningstakt av 10 °C/min. För aktiveringsprocessen som sedan producerar aktivt kol från biokolet sätts målet till att hålla en temperatur av 850 °C med en uppvärmningstakt av 11.6 °C/min. Två reaktorer designas för att skapa dom efterfrågade förhållandena. Reaktorerna värms av sekundärgas från dieselbrännare för att värma biomassan och biokolet. Värmningen sker genom att den värma sekundärgasen leds runt en roterande ståltrumma genom vilken biomassan flödar. För att kunna ha en bra kontroll av temperaturprofilen i biomassan så används två utloppsrör för gasen på reaktorernas ovansida. Genom att kontrollera gasflödet till respektive utloppsrör kan både uppvärmningstakt och stabiliteten hos temperaturen justeras. Sekundärgasens inloppsrör placeras på reaktorns undersida och riktas mot övergångszonen mellan uppvärmning och stabilisering. Reaktorerna modelleras i fysiksimuleringsprogrammet COMSOL Multiphysics 4.3b. I COMSOL simuleras driften och de parametrar som påverkar den evalueras genom att varieras mot ett referensvärde. Temperaturprofilens målområde i pyrolysreaktorn sätts till att hålla en temperatur mellan 571.5 och 628.5 °C för pyrolysen och efter uppvärmningen, om temperaturprofilen går utanför målområdet så klassas den som oacceptabel. För biokolet i aktiveringsreaktorn sätts ett liknade mål till att det ska hålla mellan 809 °C och 891 °C efter uppvärmninge

The hydraulic retention time (HRT) is one of the key parameters in biogas processes and often it is postulated that a minimum HRT of 10–25 days is obligatory in continuous stirred tank reactors (CSTR) to prevent a washout of slow growing methanogens. In this study the effects of the reduction of the HRT from 6 to 1.5 days on performance and methanogenic community composition in different systems with and without immobilization operated with simulated thin stillage (STS) at mesophilic conditions and constant organic loading rates (OLR) of 10 g L−1d−1 of volatile solids were investigated. With the reduction of the HRT process instability was first observed in the anaerobic sequencing batch reactor (ASBR) (at HRT of 3 days) followed by the CSTR (at HRT of 2 days). The fixed bed reactor (FBR) was stable until the end of the experiment, but the reduction of the HRT to 1.5 days caused a decrease of the specific biogas production to about 450 L kg−1 of VS compared to about 600 L kg−1 of VS at HRTs of 4–5 days. Methanoculleus and Methanosarcina were the dominant genera under stable process conditions in the CSTR and the ASBR and members of Methanosaeta and Methanospirillum were only present at HRT of 4 days and lower. In the effluent of the FBR Methanosarcina spp. were not detected and Methanosaeta spp. were more abundant then in the other reactors.

Continuous flow chemistry as a process intensification tool is well known. However, its ability to enable chemists to perform reactions which are not possible in batch is less well studied or understood. Here we present an example, where a new reactivity pattern and extended reaction scope has been achieved by transferring a reaction from batch mode to flow. This new reactivity can be explained by suppressing back mixing and precise control of temperature in a flow reactor set up.

Several emerging technologies for treatment or resource recovery from wastewater are based on the combination of membranes and biochemical conversions. In this chapter, we review gas-diffusion, extractive, biocatalytic, and electrochemical membrane bioreactors (MBRs). Gas diffusion MBRs facilitate efficient delivery of a gaseous oxidant or reductant such as oxygen, hydrogen, or methane to microbial biofilms treating wastewater. Extractive MBRs completely separate the wastewater stream from the microbes and make toxic wastewaters amenable to biological treatment. Biocatalytic MBRs utilize enzymes or immobilized microbial cells for degradation of persistent xenobiotics or for synthesis of fine chemicals. Electrochemical MBRs make it possible to utilize organic in wastewater for production of energy or chemicals. All four technologies are currently in the research and development stage, but can potentially contribute to more efficient removal of pollutants and recovery of resources from wastewater.

Membrane Biological Reactors: Theory, Modeling, Design, Management and Applications to Wastewater Reuse comprehensively covers the salient features and emerging issues associated with the MBR technology. The book provides thorough coverage starting from biological aspects and fundamentals of membranes, via modeling and design concepts, to practitioners’ perspective and good application examples. Membrane Biological Reactors focuses on all the relevant emerging issues raised by including the latest research from renowned experts in the field. It is a valuable reference to the academic and professional community and suitable for undergraduate and postgraduate teaching in Environmental Engineering, Chemical Engineering and Biotechnology.

Biodiesel can be produced through transesterification process with alcohols by using batch reactors with homogeneous catalysts. However, this type of operation process exhibits low efficiency along with issues on the post-treatment or recycle of homogeneous catalysts. To improve those shortcomings, new intensified continuous reactors and heterogeneous catalysts have been developed to meet both the requirement of high-efficiency and low-pollution. This chapter will summarize the recent progress of intensified reactors and new solid heterogeneous catalysts for biodiesel production, which will provide solid foundations to analyze the potential continuous reactors and solid heterogeneous catalysts for large-scale biodiesel production. Furthermore, the economic analysis and ecological issues are also demonstrated in the end., QC 20140120

The generation of globally optimal designs which can minimize capital and/or operating cost expenditures is a highly sought after objective within the chemical industry. A methodology which can systematically generate such globally optimal solutions to objective functions commonly encountered in the chemical industry is the IDEAS framework. The IDEAS framework decomposes a process network into an operator, OP network, where the unit operations (reactors, distillation columns, heat exchangers, etc.) occur, and a distribution, DN network, where the flow operations (mixing, splitting, recycling, and bypass) occur. The optimal process network structure is identified through solution of an infinite linear program (ILP) that is formulated within the IDEAS framework. The ILP's solution is approximated by finite dimensional linear programs of ever increasing size. The global optimization of complex, multi-pressure distillation networks for the separation of azeotropic mixtures using the IDEAS framework, is presented in chapter 1. The objective function in this case aims at minimizing total network flow in an effort to directly (indirectly) reduce capital (operating) costs. The global optimization of chemical reactor networks is presented in chapter 2-4. There, interesting properties relating to energy consumption and entropy generation for isothermal/isobaric reactor networks are described in the context of the attainable region (AR). Given certain assumptions, namely that all reactors are either of the endothermic or exothermic kind, a proof is presented that energy consumption and entropy generation can be rigorously identified in the infinite space of chemical reactors, independently of the network's internals (chapter 2). For the case of isothermal/isobaric chemical reactor networks where both endothermic and exothermic reactors participate in delivering the desired outlet product composition, entropy generation minimization is synonymous with an objective function of m

The potential fields of application of biocatalytic membrane reactors have widened considerably in recent years. Although biocatalytic membrane reactors, in general, are yet to achieve broad industrial application, in the not too far future they are expected to play a major role, not only for the production, transformation and valorization of raw materials but also for environmental remediations. This chapter comprehensively reviews the laboratory scale studies which demonstrate the potential of biocatalytic membrane reactors in wastewater treatment applications. Studies reponed in the literature, however, serve as proof of concept only. Issues that need to be addressed in order to achieve scale-up of such systems have been discussed in this chapter.

This paper presents the results of field measure-ments of the impedance of two commercial available wind turbine reactors, performed by a sweep frequency response analyzer, sFRA. The measurements were taken in the frequency range from 20Hz to 20MHz. Comparable frequency behavior was found in all performed measurements with significant resonances at 1MHz for the 3.6 MW reactor and 2MHz for the 2.3MW reactor. Quadratic approximation was found to be suitable for the normalized resistance variation of the 2.3MW reactor in frequencies from 20Hz to 10kHz. At frequencies below 1kHz, the normalized resistance was nearly identical for both reactors. Additionally, the accuracy of the measurement instrument was validated by comparing measurement results from two simple systems, comprising of a coil (L-system) and a series combination of coils and resistors (RL-system) with the results obtained from two high precision instruments. High accuracy of the sFRA instrument was confirmed.

Accident conditions involving significant core degradation are termed severe accidents /IAEA: NS-G-2.15/. Despite the low probability of occurrence of such events, the investigation of severe accident scenarios is an important part of the nuclear safety research. Considering a hypothetical core melt down scenario in a VVER-1000 light water reactor, the early in-vessel phase focusing on the thermal-hydraulic phenomena, and the late in-vessel phase focusing on the melt relocation into the reactor pressure vessel (RPV) lower head, are investigated. The objective of this work is the assessment of severe accident management procedures for VVER-1000 reactors, i.e. the estimation of the maximum period of time available for taking appropriate measures and particular decisions by the plant personnel. During high pressure severe accident sequences it is of prime importance to depressurize the primary circuit in order to allow for effective injection from the emergency core cooling systems and to avoid reactor pressure vessel failure at high pressure that could cause direct containment heating and subsequent challenge to the containment structure. Therefore different accident management measures were investigated for the in-vessel phase of a hypothetical station blackout accident using the severe accident code ASTEC, the mechanistic code ATHLET and the multi-purpose code system ANSYS. The analyses performed on the PHEBUS ISP-46 experiment, as well as simulations of small break loss of coolant accident and station blackout scenarios were used to contribute to the validation and improvement of the integral severe accident code ASTEC. Investigations on the applicability and the effectiveness of accident management procedures in the preventive domain, as well as detailed analyses on the thermal-hydraulic phenomena during the early in-vessel phase of a station blackout accident have been performed with the mechanistic code ATHLET. The results of the simulations show, that the effec

In large-scale microalgal production in tubular photobioreactors, the build-up of O2 along the tubes is one of the major bottlenecks to obtain high productivities. Oxygen inhibits the growth, since it competes with carbon dioxide for the Rubisco enzyme involved in the CO2 fixation to generate biomass. The effect of oxygen on growth of Nannochloropsis sp. was experimentally determined in a fully controlled flat-panel photobioreactor operated in turbidostat mode using an incident photon flux density of 100 µmol photons m-2 s-1 and with only the oxygen concentration as variable parameter. The dissolved oxygen concentration was varied from 20 to 250% air saturation. Results showed that there was no clear effect of oxygen concentration on specific growth rate (mean of 0.48¿±¿0.40 day-1) upon increasing the oxygen concentration from 20% to 75% air saturation. Upon further increasing the oxygen concentration, however, a linear decrease in specific growth rate was observed, ranging from 0.48¿±¿0.40 day-1 at a dissolved oxygen concentration of 75% air saturation to 0.18¿±¿0.01 day-1 at 250% air saturation. In vitro data on isolated Rubisco were used to predict the quantum yield at different oxygen concentrations in the medium. The predicted decrease in quantum yield matches well with the observed decrease that was measured in vivo. These results indicate that the effect of oxygen on growth of Nannochloropsis sp. at low light intensity is only due to competitive inhibition of the Rubisco enzyme. At these sub-saturating light conditions, the presence of high concentrations of oxygen in the medium induced slightly higher carotenoid content, but the increased levels of this protective antioxidant did not diminish the growth-inhibiting effects of oxygen on the Rubisco.

La tesis versa sobre el análisis de las necesidades detectadas en la construcción de un reactor a escala de laboratorio para simular las condiciones de trabajo de distintos modelos de reactores para depurar aguas residuales mediante biomasa fija sobre soportes de diversa índole. Abstract: This document is about the identification and detection of some of the parameters that are needed for make a laboratory reactor tha can simulate some of the types that are in the market for the depuration of sewage.

V-(4-5) wt.% Cr-(4-5) wt.% Ti alloys are important candidate structural materials for the first-wall and blanket in future fusion reactor. Thus it is necessary to study the fundamental mechanical properties and the irradiation effects of the V-based alloys. Within a random solid solution model, the elastic constants and ideal strength of the V-4Cr-4Ti and the V-5Cr-5Ti alloys were calculated and compared with those of pure V solid. According to the theoretical Cauchy pressure and the ratio of bulk modulus and shear modulus, both alloys exhibit good ductility. Within the 250-atom supercell, inclusion of one vacancy defect or one interstitial H (He) atom will further enhance the ductility of these alloys., QC 20110809

Membrane biological reactors combine the use of biological processes and membrane technology to treat wastewater. The use of biological treatment can be traced back to the late nineteenth century. It became a standard method of wastewater treatment by the 1930s (Rittmann, 1987). Both aerobic and anaerobic biological treatment methods have been extensively used to treat domestic and industrial wastewater (Visvanathan et al., 2000). After removal of the soluble biodegradable matter in the biological process, any biomass formed needs to be separated from the liquid stream to produce the required effluent quality. In the conventional process, a secondary settling tank is used for such solid/liquid separation and this clarification is often the limiting factor in effluent quality (Benefield and Randall, 1980).

In the last decades, membrane catalysis has been studied by several research and the significant progress in this field is summarized in several review articles (Armor 1998, Lin 2001, Lu 2007, Mcleary 2006, Sanchez 2002, Saracco 1994, Shu 1991). Considering a IUPAC definition (Koros 1996), a membrane reactor (MR) is a device for simultaneously performing a reaction (steam reforming, dry reforming, autothermal reforming, etc.) and a membrane-based separation in the same physical device. Therefore, the membrane not only plays the role of a separator, but also takes place in the reaction itself. The term Membrane Bioreactor (MBR), on the other hand, refers to the coupling of biological treatment with membrane separation in contrast to the sequential application of membrane separation downstream of classical biotreatment (Judd 2008, Visvanathan 2000). This chapter comprises a review of both MR (section 1-4) and MBR (section 5).

This chapter presents a comprehensive analysis and modelling of the Tennessee Eastman challenge problem. Both a simplified model of the system as well as a full process model that includes the energy balances is given. In each case a full model analysis is carried out to establish the degrees of freedom (DoF) and the appropriate selection of variables to satisfy the DoF. Of major concern is the control of the process. The chapter considers the open-loop dynamics of the flowsheet as well as the closed loop responses. Plots show the reactor dynamic behaviour as well as stripper exit flowrates. All problem data are given and initial conditions for dynamic runs are stated to enable readers to replicate the model performance.

China’s nuclear industry has undergone rapid growth in recent years and is projected to further expand in the coming decades. Accounting for almost 40 percent of all nuclear reactors either under construction or that have been approved globally, the expansion of China’s nuclear capacities has largely been driven by increasing demands for energy to support continued economic growth. Constraints include human resources, fuel supply, and the extent to which China can develop indigenous nuclear power capacities. The role of civil–military integration in this industry is yet to be determined partly as a result of the deliberate decision by Beijing to keep its nuclear weapons segment separate from its civilian operations.

Effective thermal conductivity (ETC) is an important parameter describing the thermal behaviour of packed beds with a stagnant or dynamic fluid, and has been extensively examined in the past decades. Recently, an approach of coupled discrete particle simulation (DPS) and computational fluid dynamics (CFD) has been extended to predict the ETC, allowing the elucidation of the underlying heat transfer mechanisms at a particle scale. However, because of the sensitivity of heat transfer to particle-particle contact, a large Young's modulus and small time step have to be employed in the DPS to generate accurate results, resulting in a high computational cost. This paper proposed a method to overcome this problem. It is done by introducing a correction coefficient in the calculation of the particle- particle contact radius between colliding particles. The treatment is first implemented in our recent DPS-CFD modeling of the heat transfer in gas fluidization, and is validated by comparing the predicted ETC with literature data. The effects of model parameters, particle size, and bed average temperature on ETC are also analyzed.

The need for energy is growing in the world and the market of nuclear power is now once more expanding. Some issues of the current light-water reactors can be solved by the next generation of nuclear power, Generation IV, where sodium-cooled reactors are one of the candidates. Phénix was a French prototype sodium-cooled reactor, which is seen as a success. Although it did encounter an earlier unexperienced phenomenon, A.U.R.N., in which a negative reactivity transient followed by an oscillating behavior forced an automatic emergency shutdown of the reactor. This phenomenon lead to a lot of downtime of the reactor and is still unsolved. However, the most probable cause of the transients is radial movements of the core, referred to as core-flowering. This study has investigated the available documentation of the A.U.R.N. events. A simplified model of core-flowering was also created in order to simulate how radial expansion affects the reactivity of a sodium-cooled core. Serpent, which is a Monte-Carlo based simulation code, was chosen as calculation tool. Furthermore, a model of the Phénix core was successfully created and partly validated. The model of the core has a k_eff = 1.00298 and a neutron flux of (8.43+-0.02)!10^15 neutrons/cm^2 at normal state. The result obtained from the simulations shows that an expansion of the core radius decreases the reactivity. A linear approximation of the result gave the relation: change in k_eff/core extension = - 60 pcm/mm. This value corresponds remarkably well to the around - 60 pcm/mm that was obtained from the dedicated core-flowering experiments in Phénix made by the CEA. Core-flowering can recreate similar signals to those registered during the A.U.R.N. events, though the absence of trace of core movements in Phénix speaks against this. However, if core-flowering is the sought answer, it can be avoided by design. The equipment that registered the A.U.R.N. events have proved to be insensitive to noise. Though, the high ampli

Les cambres de combustió per a endoreactors de tipus híbrid presenten un front de flama molt estable, una estabilitat que garanteix una seguretat intrínseca en el funcionament d'aquest tipus de motor coet, però que al mateix temps impedeix l'obtenció de prestacions competitives respecte als endoreactors sòlids i líquids utilitzats tradicionalment. En aquest TFC s'ha estudiat el disseny de geometries de la cambra de combustió que permetin augmentar l'eficiència de la combustió i la velocitat de regressió del gra de combustible sòlid. S'ha emprat el software de mallat Gambit i del de dinàmica de fluids computacional Fluent amb els qual s'han dissenyat les diferents geometries de cambra de combustió, i el posterior comportament fluidodinàmic. S'ha introduit a Fluent la cinètica de les reaccions químiques que permet simular la reacció entre un oxidant i un comburent el més proper possible als que s'utilitzen en l'actualitat.

Shrimps have been a popular raw material for the burgeoning marine and food industry contributing to increasing marine waste. Shrimp waste, which is rich in organic compounds is an abundant source of chitin, a natural polymer of N-acetyl-D-glucosamine (GluNac), a reducing sugar. For this respect, chitinase-producing fungi have been extensively studied as biocontrol agents. Locally isolated Trichoderma virens UKM1 was used in this study. The effect of agitation and aeration rates using colloidal chitin as control substrate in a 2-l stirred tank reactor gave the best agitation and aeration rates at 200 rpm and 0.33 vvm with 4.1 U/l per hour and 5.97 U/l per hour of maximum volumetric chitinase activity obtained, respectively. Microscopic observations showed shear sensitivity at higher agitation rate of the above system. The oxygen uptake rate during the highest chitinase productivity obtained using sun-dried ground shrimp waste of 1.74 mg of dissolved oxygen per gram of fungal biomass per hour at the kappaL a of 8.34 per hour.

Performance of controllers applied in biotechnological production is often below expectation. Online automatic tuning has the capability to improve control performance by adjusting control parameters. This work presents automatic tuning approaches for model reference specific growth rate control during fed-batch cultivation. The approaches are direct methods that use the error between observed specific growth rate and its set point; systematic perturbations of the cultivation are not necessary. Two automatic tuning methods proved to be efficient, in which the adaptation rate is based on a combination of the error, squared error and integral error. These methods are relatively simple and robust against disturbances, parameter uncertainties, and initialization errors. Application of the specific growth rate controller yields a stable system. The controller and automatic tuning methods are qualified by simulations and laboratory experiments with Bordetella pertussis.