The turbulence structure over the sea was studied with the emphasis on humidity. The data sets used came from the island of Östergarnsholm outside Gotland in the Baltic Sea. The study included spectral and quadrant analyses of the wind, temperature and humidity parameters from one measuring level. The wave state of the sea was deduced from data from a wave rider buoy anchored 4 km from the site.Two turbulence instruments for humidity were compared, the MIUU instrument (hot wire) and an open pass infrared gas analyser from LI-COR. The comparison showed that the LI-COR instrument resolved the high frequency fluctuations of the humidity better. The unstable cospectra of the sensible and latent heat fluxes were studied and categorised. It was found that many cospectra have two or more maxima. The higher frequency maxima gained influence when the stratification became near neutral.The quadrant analyses showed that the structures of humidity flux were similar to those of the heat flux. The sources of the flux were studied using different ratios. The ratio between events of moist updrafts and dry downdrafts were extensively studied. It was shown that the events of moist updrafts were more dominating during swell than during growing sea. When the results of the spectral and quadrant analyses were combined, it was shown that the smaller sized eddies of heat dominate the events of warm updrafts and that the large eddies dominate the cold downdrafts. The bulk transfer number for moisture, the Dalton number (CE), was found to be almost constant with stratification for unstable runs. The mean value was calculated to (1.0±0.3)·10-3. / Målet för denna studie var turbulensstrukturer över hav med särskild tonvikt på fuktigheten. I denna studie har använts observationer från en mast på ön Östergarns-holm, strax öster om Gotland. Arbetet innefattar spektral- och kvadrantanalys av vind, temperatur och fuktighet från en mätnivå. Havets aktuella tillstånd mättes med en vågboj förtöjd 4 km från masten. Två turbulensinstrument för fuktighet jämfördes, MIUU-instrumentet (varmtråds-instrument) och ett instrument från företaget LI-COR som mäter infraröd absorption. Jämförelsen visade att LI-COR-instrumentet löser upp de högfrekventa fuktighets-fluktuationerna bättre. Instabila cospektra för sensibelt och latent värmeflöde studerades och kategoriserades. Det visade sig att många cospektra hade två eller flera maxima. Det högfrekventa maximumet fick ökad betydelse när skiktningen blev nära neutral. Kvadrantanalyserna visade att strukturerna för värme- och fuktighetsflödet är liknande. Källan för flödena studerades med hjälp av olika kvoter. Av särskilt intresse var kvoten mellan tillfällen med fuktiga uppvindar och torra nedvindar. Det visade sig att tillfällen med fuktiga uppvindar var mer dominerande vid dyning än vid upp-byggande vågor. När resultaten från spektral- och kvadrantanalysen kombinerades, visade det sig att de små virvlarna med värme dominerar vid tillfällen med varma uppvindar och att de stora virvlarna dominerar vid kalla nedvindar. Utbyteskoefficienten CE för fuktighet, även kallad Dalton-talet, är nästan konstant för de instabila fallen. Medelvärdet av CE beräknades till (1,0±0,3)·10-3.

<p>A Sliding Mode Control System for a Bidirectional DCDC Converter was designed and a low voltage prototype was constructed. The control system based its decisions solely on the latest available measurements, which improves performance when changing operative quadrant, since no memory needs reinitializing (such as for PI and state prediction methods). A boost control philosophy was presented, based on a current source approximation. The control was found to be stable without steady-state errors when the variance of the input/output dynamics was high.</p><p>The target application for the DCDC Converter is an EV (Electric Vehicle) with a flywheel driveline, which puts additional requirements of the converter. Among these are current and voltage control, bidirectionality, and a broad input voltage range.</p><p>Simulations were performed in Simulink prior to physical implementation, proving functionality of the proposed control system. The physical implementation of the control was done on a digital signal processor with code compiled from C. A median filter was designed to increase measurement efficiency for the current sensors which had shot-like noise distortions.</p>

The aim of this paper is to analyse the urban development in Dubai by means of the fourquadrant model, presented by DiPasquale and Wheaton, which represents the market for real estate use and assets. The focus is on factors such as economic growth, access to oil, population growth and the incentive of the government to promote developments in Dubai, to study how they affect the real estate market. It is observed how all these factors contribute to the expansion of the construction sector and thereby the stock of space. However, because Dubai's economy is independent of the oil sector, access to oil is solely assumed to contribute to a higher amount of disposable capital and therefore does not have any upward pressure on the rent and the price level as the remaining factors.

A Sliding Mode Control System for a Bidirectional DCDC Converter was designed and a low voltage prototype was constructed. The control system based its decisions solely on the latest available measurements, which improves performance when changing operative quadrant, since no memory needs reinitializing (such as for PI and state prediction methods). A boost control philosophy was presented, based on a current source approximation. The control was found to be stable without steady-state errors when the variance of the input/output dynamics was high. The target application for the DCDC Converter is an EV (Electric Vehicle) with a flywheel driveline, which puts additional requirements of the converter. Among these are current and voltage control, bidirectionality, and a broad input voltage range. Simulations were performed in Simulink prior to physical implementation, proving functionality of the proposed control system. The physical implementation of the control was done on a digital signal processor with code compiled from C. A median filter was designed to increase measurement efficiency for the current sensors which had shot-like noise distortions.

This thesis concerns the occurrence of the large-scale bed and plan forms known as alternate bars and meandering, and the internal structures of the flow associated with their formation. The work is to be viewed as an extension of previous work by da Silva (1991), Yalin (1992), and Yalin and da Silva (2001). As a first step in this work, the criteria for occurrence of alternate bars and meandering of Yalin and da Silva (2001) is re-considered in view of additional field and laboratory data from the recent literature and data resulting from two series of experimental runs carried out in two sediment transport flumes. This leads to a number of modifications of the boundary-lines in the related existence-region diagram of Yalin and da Silva. The size of the largest horizontal coherent structures (HCS’s) of an alternate bar inducing flow was then investigated experimentally on the basis of three series of flow velocity measurements. These were carried out in a 21m-long, 1m-wide straight channel, conveying a 4cm-deep flow. The bed consisted of a silica sand having a grain size of 2mm; its surface was flat. The measurements were carried out using a Sontek 2D Micro ADV. The horizontal burst length was found to be between five and seven times the flow width. The effect of the HCS’s on the mean flow was also investigated. A slight internal meandering of the flow caused by the superimposition of burst-sequences on the mean flow was clearly detectable. Finally, with the aid of three new series of measurements in the same channel, an attempt was made to penetrate the dynamics and life-cycle of the HCS’s. For this purpose, quadrant analysis was used; the cross-sectional distribution of relevant statistical turbulence-related parameters was investigated; and cross-correlations of flow velocity along the flow depth and across the channel were performed. The analysis indicates that the HCS’s originate near the channel banks, with the location of ejections and sweeps being anti-symmetrically arranged with regard to the channel centreline, and then evolve so as to occupy the entire depth of the water and the entire width of the channel. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2010-03-09 10:20:53.596

The emergence of closed-loop Brayton cycle power plants, such as the PBMR, resulted in the need to simulate start-up transients for industrial multi-stage axial flow compressors operating at subsonic conditions. This implies that the delivery pressure and power requirements must be predicted for different mass flow rates and rotational speeds while operating in the first and fourth quadrants on the compressor performance charts. Therefore, an analytical performance prediction model for subsonic multi-stage axial flow compressors had to be developed that can be integrated into a generic network analysis software code such as Flownex. For this purpose, performance calculations based on one-dimensional mean-line analysis demonstrated good accuracy, provided that the correct models for losses, incidence and deviation are used. Such a model is therefore the focus of this study. A preliminary analytical performance prediction code, with the capability of interchanging between different deviation and loss models is presented. Reasonably complex loss models are integrated in association with the correct incidence and deviation models in a software package called "Engineering Equation Solver" (EES). The total pressure loss calculations are based on a superposition of theoretically separable loss components that include the following: blade profile losses, secondary losses and annulus losses. The fundamental conservation equations for mass, momentum and energy for compressible "rotating pipe" flow were implemented into the performance prediction code. Performance prediction models were validated against experimental data and evaluated according to their ease of implementation. Verification was done by comparing simulation results with experimental work done by Von Backstrom. This includes a calculation to determine the uncertainty in the experimental results. Furthermore, since the conventional definition of isentropic efficiency breaks down at the boundaries of quadrants on the performance charts, a new non-dimensional power formulation is presented that allows for the calculation of the compressor power in all of the relevant quadrants. Good comparison was found between simulation results and measurements in the first and fourth quadrant of operation. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2007.

The diploma thesis defines questions of multi level marketing. This business method still expands very fast among people, who look for new ways of growing their revenue. This thesis identifies reasons for long-term expansion especially in this branch. Simultaneously in the diploma thesis I describe way of communication during dealing with particular distributors. More this thesis involves manual for starting distributors in the branch of multi level marketing.

The aim of this thesis is to design a step-up DC/AC converter, an inverter from 12 V to 120 Vrms, with a sinus output signal. The converter should deliver a continuous performance of 300 W and a double peak power output of 600 W. The supposed usage of this inverter would be as a back-up power source for the circulatory pump of the central heating in the case of power outage. The inverter is consisting of a T-type power section.

I det teknikväxande samhället bidrar mjukvaruutveckling till stora it-relaterade utgifter och investeringar. Industrier utvecklar stödjande programvara för sin produktion och mjukvaruföretag levererar digitala system för kunder som behöver uppfylla ett behov. Utvecklingsteamen jobbar under press för att leverera så bra programvara som möjligt och samtidigt hålla sig inom budgetramar som satts upp enligt avtal. För att nå sina mål kan utvecklare introducera teknisk skuld i systemen, dvs. att bristfälliga lösningar byggs före kvalitetslösningar. Teknisk skuld behöver inte vara ett problem för stunden men på sikt kan konsekvenserna av skulderna bli problematiska och kräva resurser att kunna hanteras. Tidigare forskning visar att drygt en fjärdedel av en utvecklares tid går åt för att hantera teknisk skuld. Vid åtgärdande av teknisk skuld brukar refaktorisering vara ett vanligt verktyg att ta till, vilket innebär att skriva om källkod utan att förändra det visuella beteendet för användaren. Syftet med följande uppsats är att undersöka olika branscher som utvecklar mjukvaraoch deras hantering av teknisk skuld genom att belysa vilka faktorer som avgör om och när refaktorisering skall ske, och hur argumentationerna för refaktorisering skiljer sig åt mellan branscherna. Uppsatsen baseras på kvalitativa intervjuer med aktörer från både industri- och mjukvaruföretag. Empirin från intervjuerna analyseras med hjälp av en ontologisk mappning kring typer av teknisk skuld, som sedan har applicerats i ramverket Technical Debt Quadrant. Resultatet visar att industribranschens avgörande faktorer för refaktorisering var konsekvensen av skuldens påverkan samt hur pass förändringsbenägen den skuldbelagda funktionaliteten var. Branschen ansåg att tidpunkten för att refaktoriseravar bäst lämpad i samband med vidareutveckling av en funktion som innehöll teknisk skuld. I konstrast visade resultatet för mjukvarubranschen att faktorerna för refaktorisering var konsekvensen av skuldens påverkan samt vilka ekonomiska förutsättningar som fanns för projektet. Tidpunkten för när refaktorsering var lämplig avgörs när företagen anser att avkastningen för investeringen att refaktorisera är som högst eller när inget annat val finns. Resultatet visar även att branscherna hade olika fokus för hur de argumenterar för refaktorisering. Industrin argumenterade mer med systemet i fokus, hur det kundeförändras med tiden och att det skulle bli lätthanterligt att underhålla med tiden. Mjukvarubranschen hade mer ekonomiska aspekter som argument, dvs. att de analyserade situationen och beslutade huruvida refaktoriseringen är lönsam eller inte. / In the technology-growing society, software development contributes to large itrelated expenditures and investments. Industrial companies develop supporting software for its production and software companies deliver digital systems for customers to satisfy a need. The development teams work under pressure to deliver as good software as possible and at the same time stay within budget frameworks according to agreements. To achieve their goals technical debt in systems can be introduced, which means that deficient solutions are built before quality solutions. Technical debt does not have to be a problem at first, but in the long run the consequences of the debts can become problematic and require resources to be managed. When fixing technical debt, refactorization is a common tool to resort to, which means to rewrite source code without changing the visual behaviour to the user. Previous research shows that just over a quarter of a developer's time is spent managing technical debt. The purpose of the thesis is to examine different industries that develop software and their management of technical debt by highlighting which factors determine if and when refactoring should take place, and how the arguing for refactorization differentiate between the industries. The thesis is based on qualitative interviews with actors from both industrial and software companies. The empirical data from the interviews are analysed with the help of an ontological mapping around types of technical debt, and later applied in the framework Technical Debt Quadrant. The results show that the industry companies' decisive factors for refactorization were the consequence of the debt's impact and how prone to change the indebtedness functionality was. The industry considered that the time to refactorize was best suited in connection with the further development of a function that contains technical debt. In contrast, for the software companies the results showed that the factors for refactorization were the consequences of the debt's impact and what financial prerequisites there were for the project. Appropriate timing for refactoring wasdetermined when the companies consider that the return on the investment to refactorize is at its highest or when there is no other choice. The results also show that the industries had different focus on how they argue for refactorization. The industry argued more with the system in focus, how it could change over time and that it should be easy to maintain while the software industry had more economic aspects as an argument, ie. that they analyzed the situation and made choices whether the refactorization is profitable or not.

Afin de maintenir une bonne qualité de l’électricité, les gestionnaires de réseaux doivent maintenir les niveaux de tension harmonique en-dessous de certaines limites spécifiées dans les normes. Les niveaux de tension harmonique résultent des équipements non-linéaires présents dans les installations, qui injectent des courants harmoniques sur le réseau.Dans ce but, une solution consiste à appliquer des limites d’émission à ces installations. Les gestionnaires de réseaux ont besoin pour cela d’un indicateur fiable pour évaluer le niveau d’émission harmonique d’une installation.Dans ce cadre, nous nous sommes tout d’abord intéressés aux différentes méthodes existantes, que nous avons appliqué sur des cas de réseaux simplifiés afin de les évaluer sur plusieurs critères. Nous avons ainsi identifié dans un premier temps les définitions qui répondent le mieux à notre besoin ainsi que leurs limites restectives. Dans un deuxième temps, nous avons amélioré une des définitions retenues en proposant une nouvelle solution : la définition “quatre quadrants”.Cette nouvelle définition permet d’évaluer le courant harmonique émis par une installation sur le réseau en se basant sur les mesures de la tension et du courant au point de livraison de l’installation. Son principal intérêt par rapport aux méthodes existantes est de mieux identifier les installations moyennement perturbatrices sur le réseau. Ce point a été validé en simulation sur un réseau dérivé du benchmark CIGRE. / In order to maintain good power quality, Distribution Systems Operators (DSOs) must keep harmonic voltage levels under limits specified in standards. These harmonic voltages result from non-linear equipment connected in installations, which inject harmonic currents into networks.A possible solution to solve this problem consists to implement emission limits per installation. In order to apply these limits, DSOs need to have an accurate and reliable indicator to assess the harmonic emission of an installation.In this context, we studied different methods from the literature. We implemented each of them on several simplified distribution networks in order to evaluate them on several criteria. First, we identified the most interesting definitions from the literature, and emphasized their respective theorical limits. Then, we improved one of these definitions by proposing a new solution: the “four-quadrants” definition.This new definition is able to assess the harmonic current injected by an installation into the network by using current and voltage measurements at the point of common coupling of this installation. Its main advantage in comparison to other methods is a better detection of “medium” disturbing installations over the network. This advantage has been confirmed by implementing the proposed solution in simulation on a distribution network derived from the CIGRE benchmark.