Metodologia Per la Caratterizzazione di amplificatori a basso rumore per UMTS

In questo lavoro si presenta una metodologia di progettazione elettronica a livello di sistema, affrontando il problema della caratterizzazione dello spazio di progetto dell' amplificatore a basso rumore costituente il primo stadio di un front end a conversione diretta per UMTS realizzato in tecnologia CMOS con lunghezza di canale .18u. La metodologia è sviluppata al fine di valutare in modo quantititativo le specifiche ottime di sistema per il front-end stesso e si basa sul concetto di Piattaforma Analogica, che prevede la costruzione di un modello di prestazioni per il blocco analogico basato su campionamento statistico di indici di prestazioni del blocco stesso, misurati tramite simulazione di dimensionamenti dei componenti attivi e passivi soddisfacenti un set di equazioni specifico della topologia circuitale. Gli indici di prestazioni vengono successivamente ulizzati per parametrizzare modelli comportamentali utilizzati nelle fasi di ottimizzazione a livello di sistema. Modelli comportamentali atti a rappresentare i sistemi RF sono stati pertanto studiati per ottimizzare la scelta delle metriche di prestazioni. L'ottimizzazione dei set di equazioni atti a selezionare le configurazione di interesse per il campionamento ha al tempo stesso richiesto l'approfondimento dei modelli di dispositivi attivi validi in tutte le regioni di funzionamento, e lo studio dettagliato della progettazione degli amplificatori a basso rumore basati su degenerazione induttiva. Inoltre, il problema della modellizzazione a livello di sistema degli effetti della comunicazione tra LNA e Mixer è stato affrontato proponendo e analizzando diverse soluzioni. Il lavoro ha permesso di condurre un'ottimizzazione del front-end UMTS, giungendo a specifiche ottime a livello di sistema per l'amplificatore stesso

Rocketdyne/Westinghouse nuclear thermal rocket engine modeling

The topics are presented in viewgraph form and include the following: systems approach needed for nuclear thermal rocket (NTR) design optimization; generic NTR engine power balance codes; rocketdyne nuclear thermal system code; software capabilities; steady state model; NTR engine optimizer code-logic; reactor power calculation logic; sample multi-component configuration; NTR design code output; generic NTR code at Rocketdyne; Rocketdyne NTR model; and nuclear thermal rocket modeling directions

Analytical Optimal Design of a Two-Phase Axial-Gap Transverse Flux Motor

Transverse flux motors (TFMs) are being investigated to be used in vehicle traction applications due to their high torque density. In this paper, a two-phase axial-gap transverse flux motor is designed for an electric scooter, proposing a novel analytical design method. First, the dimensioning equations of the motor are obtained based on the vehicle requirements, and the stationary dq model is calculated. Then, the motor is optimized using a multiobjective genetic algorithm, and finally a 3D-FEM verification is made. Both the motor structure and the design method aim to have a low complexity, in order to favor the sizing and manufacturing processes through a low computation time and simple core shapes. This approach has not yet been explored in axial-gap TFMs

Using BIM capabilities to improve existing building energy modelling practices

Purpose - This paper presents a review of the implications Building Information Modelling (BIM) is having on the building energy performance modelling (BEM) and design of buildings. It addresses the issues surrounding exchange of information throughout the design process, and where BIM may be useful in contributing to effective design progression and information availability. Design/methodology/approach - Through review of current design procedures and examination of the concurrency between architectural and thermophysical design modelling, a procedure for in- formation generation relevant to design stakeholders is created, and applied to a high-performance building project currently under development. Findings - The extents of information key to the successful design of a buildings energy performance in relation to its architectural objectives are given, with indication of the Level of Development (LOD) required at each stage of the design process. Practical Implications - BIM offers an extensible medium for parametric information storage, and its implementation in design development suggests the capability for inclusion of building performance data integration. The extent of information required for accurate BEM at stages of a building’s design is defined to assist comprehensive recording of performance information in a BIM environment. Originality/value - This paper contributes to the discussion around the integration of concurrent design procedures and a Common Data Environment (CDE). It presents a framework for the creation and dissemination of information during design, exemplifies this on a real building project and evaluates the barriers experienced in successful implementation

Optimisation and Operation of Residential Micro Combined Heat and Power (μCHP) Systems

In response to growing concerns regarding global warming and climate change, reduction of CO2 emissions becomes a priority for many countries, especially the developed ones such as the UK. Residential applications are considered among the most important areas for substantial reduction of CO2 emissions because they represent a major part of the total consumed energy in those countries. For instance, in the UK, residential applications are currently accountable for about 150 Mt CO2 emissions, which represents approximately 25% of the whole CO2 emissions [1-2]. In order to achieve a significant CO2 reduction, many strategies must be adopted in the policy of these countries. One of these strategies is to introduce micro combined heat and power (μCHP) systems into residential energy systems, since they offer several advantages over traditional systems. A significant amount of research has been carried out in this field; however, in terms of integrating such systems into residential energy systems, significant work is yet to be conducted. This is because of the complexity of these systems and their interdependency on many uncertain variables, energy demand of a house is a case in point. In order to achieve such integration, this research focuses on the optimisation and operation of μCHP systems in residential energy systems as essential steps towards integration of these systems, so it deals with the optimisation and operation of a μCHP system within a building taking into account that the system is grid-connected in order to export or import electricity in certain cases. A comprehensive review that summarises key points that outline the trend of previous research in this field has been carried out. The reviewed areas include: technologies used as residential μCHP units, modelling of the μCHP systems, sizing of μCHP systems and operation strategies used for such systems. To further this, a generic model for sizing of μCHP system’s components to meet different residential application has been developed by the author. Two different online operation strategies of residential μCHP systems, namely: an online linear programming optimiser (LPO) and a real time fuzzy logic operation strategy (FLOS) have been developed. The performance of the novel online operation strategies, in terms of their ability to reduce operation costs, has been evaluated. Both the LPO and the FLOS were found to have their advantages when compared with the traditional operation strategies of μCHP systems in terms of operation costs and CO2 emissions. This research should therefore be useful in informing design and operation decisions during developing and implementing μCHP technologies in residential applications, especially single dwellings

Technical and economic appraisal for harnessing a proposed hybrid energy system nexus for power generation and CO2 mitigation in Cross River State, Nigeria

By creating hybrid energy systems and obtaining a framework that equally satisfies a continuous operation for renewable energy technology, this study presents renewable and sustainable energy options as an integral method to energy transitioning from non-renewable to renewable energy utilization in Cross River State, Nigeria. For a needed load of 2424.25 kWh/day in Cross River State, this study focused on proposing a designed hybrid energy system (HES) nexus, mitigating CO2, and appraisal of the technical and economic viability. To accomplish this, HOMER software was utilized in simulating the ideal components that suggested a HES nexus. The software enabled the selection of the optimal HES using various renewable energy sources since it predicts future electrical demand, wind speed, solar irradiation, and temperature. Economic results obtained showed that the proposed HES's Levelized cost of energy (LCOE), net present cost (NPC), and operating cost (OC) were $0.89/kWh,$10,138,702 and $134,084.37 respectively. Further technical appraisal showed that the renewable energy conversion systems (RECs) make up 78.74% of the proposed HES. The photovoltaic (PV) arrays were primarily responsible for the hybrid energy system's electricity output. The annual electrical energy output was 1,984,111kWh (89.4%), produced by the PV arrays. The generic fuel cell produced the least, at 29,957kWh/year, accounting for just 1.35% of the total electricity produced. However, the wind power plant produced 205,365kWh/year annually. Furthermore, comparing the HES with diesel-powered generators, the system achieves a net-zero carbon emission status. Therefore, it has proven to be the most reliable energy as it will solve the problem of energy demand and reduces carbon emissions in Cross River State, Nigeri

Reconfigurable photovoltaic systems. Practical approach to TEAM systems

Although solar energy plays a vital role in pursuing sustainable development and addressing climate change, several challenges hinder its widespread development. Solar power generation relies on sunlight availability, making it intermittent and dependent on weather conditions. Additionally, the initial cost, integration into power grids, and storage of surplus energy present serious challenges. However, ongoing research and development efforts aim to overcome these obstacles and enhance the efficiency, affordability, and reliability of solar energy systems. Accordingly, the objective of this thesis is to explore the efficiency of grid-connected photovoltaic (GCPV) systems. The significance lies in the fact that even a slight improvement in efficiency can have a profound impact, making solar energy more accessible and cost-effective. In this regard, a numerical method is used to evaluate the energy flows in the system and the plantoriented (PO) configuration is selected as the architecture of GCPV systems. Arduino, relay, solar array simulator, power meter, ports, inverters, and MATLAB form a GCPV system. Fixed and team systems which are arrangements of inverters and PV arrays are selected to be emulated. Fixed systems are working with two parallel inverters and team systems are able to select working with one or two inverters. In this case, some calculations are done to find the best switching points. Additionally, a switching problem arises which has been addressed in the report. The emulation of total energy capturing and processing processes have been conducted and the results are compared. It is worth mentioning that these emulations are performed according to several weather conditions or irradiation levels. Finally, the results of these real-time emulations show the disparity in the energies delivered to the grid that proves the effect of the configuration on efficiency.Encara que l'energia solar juga un paper vital en la recerca de desenvolupament sostenible i en l'abordatge del canvi climàtic, diversos reptes dificulten el seu desenvolupament generalitzat. La generació d'energia solar depèn de la disponibilitat de llum solar, la qual cosa la fa intermitent i dependent de les condicions climàtiques. A més, el cost inicial, la integració en les xarxes elèctriques i l'emmagatzematge de l'excedent d'energia presenten reptes importants. No obstant això, els esforços continus de recerca i desenvolupament tenen com a objectiu superar aquests obstacles i millorar l'eficiència, l'accessibilitat i la fiabilitat dels sistemes d'energia solar. En conseqüència, l'objectiu d'aquesta tesi és explorar l'eficiència dels sistemes fotovoltaics connectats a la xarxa (GCPV, per les seves sigles en anglès). La importància rau en el fet que fins i tot una lleugera millora en l'eficiència pot tenir un gran impacte, fent que l'energia solar sigui més accessible i rendible. En aquest sentit, s'utilitza un mètode numèric per avaluar els fluxos d'energia en aquests sistemes i es selecciona la configuració orientada a la planta (PO) com l'arquitectura dels sistemes GCPV. Controladors Arduino, commutadors controlats, simuladors de generadors fotovoltaics, mesuradors d'energia i inversors fotovoltaics de connexió a la xarxa formaran part dels sistemes GCPV a provar, utilitzant MATLAB com a programari de control. Es simularan sistemes fotovoltaics de configuració estàtica i sistemes fotovoltaics de configuració dinàmica del tipus TEAM. Els sistemes de configuració estàtica funcionen amb dos inversors en paral·lel i els sistemes TEAM poden seleccionar treballar amb un o dos inversors. En aquest cas, es realitzen alguns càlculs per trobar els millors punts de commutació. A més, sorgeix un problema de commutació que s'aborda en l'informe. S'han dut a terme les simulacions dels processos totals de captura i processament d'energia i s'han comparat els resultats. Val la pena destacar que aquestes simulacions es realitzen segons diferents condicions climàtiques o nivells de radiació. Finalment, els resultats d'aquestes simulacions en temps real mostren la disparitat en les energies lliurades a la xarxa, la qual cosa demostra l'efecte de la reconfiguració en l'eficiència.Aunque la energía solar desempeña un papel vital en la búsqueda del desarrollo sostenible y en abordar el cambio climático, varios desafíos dificultan su desarrollo generalizado. La generación de energía solar depende de la disponibilidad de luz solar, lo que la hace intermitente y dependiente de las condiciones climáticas. Además, el costo inicial, la integración en las redes eléctricas y el almacenamiento del excedente de energía presentan desafíos importantes. Sin embargo, los esfuerzos continuos de investigación y desarrollo tienen como objetivo superar estos obstáculos y mejorar la eficiencia, la accesibilidad y la confiabilidad de los sistemas de energía solar. En consecuencia, el objetivo de esta tesis es explorar la eficiencia de los sistemas fotovoltaicos conectados a la red (GCPV, por sus siglas en inglés). La importancia radica en el hecho de que incluso una ligera mejora en la eficiencia puede tener un gran impacto, haciendo que la energía solar sea más accesible y rentable. En este sentido, se utiliza un método numérico para evaluar los flujos de energía en estos sistemas y se selecciona la configuración orientada a la planta (PO) como la arquitectura de los sistemas GCPV. Controladores Arduino, conmutadores controlados, simuladores de generadores fotovoltaicos, medidores de energía, inversores fotovoltaicos de conexión a red formarán parte de los sistemas GCPV a ensayar, utilizándose MATLAB como software de control. Se emularán sistemas fotovoltaicos de configuración estática y sistemas fotovoltaicos de configuración dinámica del tipo TEAM. Los sistemas de configuración estática funcionan con dos inversores en paralelo y los sistemas TEAM pueden seleccionar trabajar con uno o dos inversores. En este caso, se realizan algunos cálculos para encontrar los mejores puntos de conmutación. Además, surge un problema de conmutación que se aborda en el informe. Se han llevado a cabo las emulaciones de los procesos totales de captura y procesamiento de energía, y se han comparado los resultados. Vale la pena mencionar que estas emulaciones se realizan de acuerdo a varias condiciones climáticas o niveles de radiación. Finalmente, los resultados de estas emulaciones en tiempo real muestran la disparidad en las energías entregadas a la red, lo que demuestra el efecto de la reconfiguración en la eficiencia

Operations planning and analysis handbook for NASA/MSFC phase B development projects

Current operations planning and analysis practices on NASA/MSFC Phase B projects were investigated with the objectives of (1) formalizing these practices into a handbook and (2) suggesting improvements. The study focused on how Science and Engineering (S&E) Operational Personnel support Program Development (PD) Task Teams. The intimate relationship between systems engineering and operations analysis was examined. Methods identified for use by operations analysts during Phase B include functional analysis, interface analysis methods to calculate/allocate such criteria as reliability, Maintainability, and operations and support cost

Preliminary design of a magnetorheological brake for automotive use

After an initial study of the characteristics of magnetorheological fluids based on a thorough search in literature, a preliminary configuration of MR brake is proposed. It comes from the evaluation of the main factors influencing the design of an appropriate magnetic circuit, and then the performance obtained in terms of brake torque. The analytical study of the brake has allowed a first preliminary sizing. Through the subsequent execution of an electromagnetic finite element model, created in ANSYS, it was possible to assess more accurately the distribution of the magnetic field inside the MR fluid and hence the resistance to relative motion between rotor and stator. The work needs an accurate optimization due to insufficient value of the braking torque and high mass of the device