CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Esta tese tem como objetivo central explicar/descrever padrÃes acÃsticos do tap em onset complexo na fala de crianÃas com e sem desvio fonolÃgico à luz da FonÃtica AcÃstica. TambÃm visa investigar determinados detalhes fonÃticos presentes em clusters com tap, nos quais esta consoante à precedida por consoantes oclusivas, surdas e sonoras, e pela fricativa labiodental surda, de acordo com a sintaxe fÃnica do portuguÃs brasileiro. A pergunta norteadora desta pesquisa à esta: em que medida as produÃÃes acÃsticas do tap em onset complexo se distinguem na fala de crianÃas com e sem desvio fonolÃgico? Os procedimentos metodolÃgicos consistiram na aplicaÃÃo de teste de nomeaÃÃo de figuras, visando eliciar palavras-alvo dissÃlabas paroxÃtonas, com tap em onset complexo seguido por vogal tÃnica [a]. Os testes se aplicaram a dois grupos distintos de participante: um constituÃdo de crianÃas com desvio fonolÃgico (N=4) e outro, de crianÃas sem o desvio (N=4). Para a gravaÃÃo dos dados, utilizaram-se um gravador Zoom modelo H4n (Handy Recorder), com taxa de amostragem de 44100 Hz, e um microfone de lapela. Todos os dados dos participantes foram gravados em cabine acusticamente tratada. A hipÃtese bÃsica foi a de que as produÃÃes acÃsticas do tap em onset complexo do grupo de crianÃas com desvio fonolÃgico (GDF) se distinguem significativamente das do grupo de crianÃas sem o desvio (GSDF). A anÃlise do tap se pautou pela anÃlise espectrogrÃfica e pela forma de onda. Quanto Ãs hipÃteses especÃficas, afirma-se que GDF e GSDF se distinguem quanto: (i) Ãs oclusivas surdas, sendo o parÃmetro acÃstico o VOT relativo; (ii) Ãs oclusivas sonoras, sendo o parÃmetro o VOT, vozeamento/(des-)vozeamento; (iii) à fricativa labiodental surda, sendo os parÃmetros a duraÃÃo relativa da fricativa surda e sua composiÃÃo espectral. Os resultados corroboraram a hipÃtese bÃsica. Jà em relaÃÃo à primeira hipÃtese especÃfica, constatou-se que diferenÃas hà nas produÃÃes de GDF e GSDF, mas nÃo sÃo significativas. Entretanto, considerando-se os efeitos da variÃvel sexo no VOT, encontrou-se diferenÃa significativa (p = 0,03571) em relaÃÃo à mÃdia dos valores do VOT da velar [k], sendo a mÃdia da meninas mais alta que a dos meninos. Quanto Ãs demais hipÃteses, nÃo foram encontradas diferenÃas estatisticamente significativas.

The aim of this thesis is to obtain a basic knowledge of the factors that affect corrosion of aluminium in tap water for different kinds of applications like water pipes for tap water, solar systems, HVAC&R-applications (like fan coil units on chillers) and heat sinks for electronic or industrial applications. Open systems are used in some applications and closed systems in others. There is a clear difference in the corrosion behaviour of these two systems. The main reasons for this difference are that the content of oxygen differs between the two systems and also that inhibitors can be used in closed systems to hinder corrosion. In this thesis focus will be on corrosion in open systems. The corrosion properties in tap water for different alloys of aluminium and different surface treatments have been examined. The influences on corrosion of the oxygen content in water and the iron content in aluminium alloys have been investigated. The corrosion properties of an aluminium alloy in deionised water have also been examined.

Nowadays the technologies of communication are widely developing due to the huge requirements in the world, such as asymmetric digital subscriber line (ADSL), wireless fidelity (Wi-Fi), and high definition television (HDTV). We are seeking for high performance and quality communication schemes. The scheme of orthogonal frequency division multiplexing (OFDM) catches everyone's eyes due to the advantages of the OFDM. Not only high bit rate in the long haul transmission but also reconfigurable network is the charming contention, and the penalties are reduced by the cyclic prefix which can reduce the inter-symbol interference (ISI). In this thesis, I will introduce the demand for optical fiber communications, then, interpret the motivation and the organizations in a nutshell. Next, the theoretical studies will be discussed, including mathematical formulations and basic theories of one tap equalizer, a cyclic prefix, a training symbol synchronization, and a discrete multitone (DMT) modulation. In addition, the experimental setups are successfully constructed and used for verifying the impact of one tap equalizer and the training symbol synchronization. Also, the performance of the systems are measured. Finally, the thesis is concluded.

The forwarding delay and throughput of a proxy server play significant role in the overall network performance. It is widely known that the forwarding delay of proxy¡¦s application layer is much larger than that of lower layers. This is because for a general purpose operating system, the receiving or sending data in application layer needs to move data through the TCP/IP stack and also cross the user/kernel protection boundaries. TCP Splice can forward data directly in TCP layer without going up to the application layer. This can be achieved by modifying the packet headers of one TCP connection from the original server to the proxy so that the TCP connection can be seamlessly connected to another TCP connection from the proxy to the client. To maintain the caching ability of proxy, TCP Tap can duplicate packets before they are forwarded by TCP Splice. The duplicated packets are copied into a tap buffer, so the application layer can read data from the tap buffer. We fully utilize the original TCP receive queue as the tap buffer and allow application layer to read data as usual. We chose Linux as the platform for experiment. The TCP Splice and Tap are implemented as Linux modules. Finally, we develop an HTTP proxy to test and verify our implementation. It is shown that the performance of proxy in terms of lower forwarding delay, higher throughput, and increased CPU utilization, can be improved significantly.

Brytspänningen är den spänning som uppkommer när överkopplingsmotståndet i lindningskopplaren lämnar sitt föregående läge vid omkoppling. Storleken på brytspänningen i lindningskopplaren beror på hur stor läckinduktansen är. Är den inte känd så kan brytspänningen istället beräknas med hjälp av FEM-programmet ACE (internt ABB-program) i samband med Mathcad. I ACE beräknas först reaktanserna i p.u-enheter mellan lindningarna och hur stora de är beror på lindningslayouten. Det är tidskrävande att använda ACE och Mathcad och uppgiften är att utreda de parametrar som påverkar storleken på brytspänningen samt att ta fram en förenklad beräkning av densamma. Genom simulering i ACE av en mängd olika lindningslayouter visar det sig snart att det är alltför många parametrar som påverkar reaktanserna. De förenklingar som trots det har tagits fram är lite för grova för att det ska vara pålitligt. Mathcad är än mer komplext med tunga beräkningar som inte är lätta att förenkla. Arbetet har ändå gett mer kunskap om hur reaktanserna påverkas av geometrierna i lindningarna och kommer att vara till viss nytta, även om det inte gick att förenkla ACE- och Mathcadberäkningarna så som var tänkt. / The recovery voltage is the voltage that occur when the transition resistor in the tap-changer leaves its previous position during an operation cycle. The amplitude of the recovery voltage depends on the leakage inductance. If the leakage inductance is unknown, the recovery voltage can instead be calculated using a FEM-program called ACE (internal ABB-program) in conjunction with Mathcad. First, the reactances between the windings are calculated in per unit (p.u) using ACE and they depend on the winding layout. It is time consuming to use ACE and Mathcad and the task has been to investigate the parameters that affects the recovery voltage and to develop a simplified calculation of it. Through simulation using ACE of a number of different winding layouts one soon comes to the conclusion that there are simply too many parameters affecting the reactances. Although the simplified calculations that despite this has been developed, they soon prove to be too rough to be useful. Mathcad is even more complex with heavy calculations that are not easy to grasp. However, this thesis has given more knowledge about the way the reactances are affected by the geometry of the windings, even though it was not possible to in a reasonable way simplify the calculation of ACE and Mathcad.

NY, Univ., Diss.--New York. / Includes bibliographical references (p. 301-315) and index.

Due to the increasing integration of renewable energy generations, the overvoltage and overload issues in transmission networks have become more significant, and they may occur at various locations. To mitigate the overvoltage issues, traditional solutions which often consider the installation of reactive power compensators such as shunt reactors, SVC, STATCOM may not be cost-effective. To mitigate the overload issues, traditional methods using direct or price-based demand control will affect customers’ electrical experience in that they are inconvenienced greatly. This thesis discusses the flexible tap changing techniques that utilise existing parallel transformers in distribution networks to provide reactive power absorption and demand response services for transmission systems. Among them, the tap stagger technique operates parallel transformers in small different tap positions, i.e. staggered taps, to result in more reactive power absorption from upstream networks. In addition, the tap changing technique changes voltages in the range of statutory limits through the adjustment of tap positions in order to change network demands without directly affecting customers. The aggregated reactive power absorption or demand response from many pairs of parallel transformers in distribution networks could be sufficient to provide VAr or demand support to transmission networks. Network capability studies have been carried out in OpenDSS simulation software to investigate the VAr absorption capability by using tap staggering technique and the demand reduction capability by using tap changing technique. The studies are based on two UK HV distribution networks (132-33kV) with 11 and 28 primary substations (33/11 or 6.6 kV) respectively, and the techniques are applied to parallel transformers in primary substations. Based on the results of the two networks, the capabilities of the whole ENW and the UK distribution networks have been estimated respectively by using linear estimation method. In addition, the VAr absorption capability of the tap stagger technique has been validated by using site trial data. The results show an average VAr absorption capability of 0.89MVAr for a primary substation, 315MVAr for ENW networks and about 2500MVAr for the UK at stagger level 4 and show an average demand reduction capability of 3.1% of the original demand at tap down level 3. The results of capability studies together with the validations results confirm that the flexible tap changing techniques are able to provide transmission networks with effective VAr support and demand response services. To assess network VAr absorption and demand response capability more precisely, this thesis also proposes an online load profile estimation method to estimate the load profiles of the network more accurately if not all substations in the network are monitored. The method uses Peak Load Share values, Euclidean Distance, and some load measurements to estimate load profiles. The method has been validated and compared with a traditional aggregation-based method. The results show an average estimation error of 13% ~ 23% in different conditions using the proposed method, and show an average estimation error reduction from about 47% (using the traditional method) to about 13% (using the proposed method). The results indicate that the developed method has a considerable improvement on the accuracy of load profile estimation.

The aim of this master's thesis is to deal with main thread production methods and to study the influence of coatings on tap cutting performance. The high-speed steel cutting taps with different PVD coatings (Physical Vapour Deposition) were tested, while the same cutting conditions were set. Cutting torques were measured and analysed, which together with the results of evaluation of tool wear led to conclusion.

Scaling of TLM (Transaction Level Modeling) simulations for performance is difficult. In this project I will go through several causes of poor performance. This paper describes several simulation engines that use SystemC that are connected so they together simulate next generation radio base station. It also describes how to build a virtual network in, for security reasons, constrained environment where both virtual and physical equipment can connect the simulated target. Furthermore, it describes how to use the virtual network to improve the overall performance of the simulation. It is shown how the virtual network is used to distribute the simulation and offloading the simulated target to accomplish the performance goal. / Det är svårt att skala upp en simulering baserad på TLM (Transaction Level Modeling). I detta projekt kommer jag att gå igenom flera orsaker till dålig prestanda. Denna rapport beskriver flera olika simuleringsmotorer som använder SystemC och som är kopplade så att de tillsammans simulerar nästa generation radiobasstationer. Här beskrivs också hur man bygger ett virtuellt nätverk som hanterar begränsningar som finns av säkerhetsskäl, och trots detta kan koppla ihop virtuell och fysisk utrustning till det simulerade målsystemet. Dessutom anges hur detta virtuella nät används för att förbättra den övergripande prestandan i simuleringen. Detta görs genom att utnyttja det virtuella nätet för att distribuera simuleringen och avlasta målsystemet.

On-load tap-changers (OLTC) are devices in the power grid that keeps the voltage level constant for consumers, regardless of the power demand. Hitachi ABB Power Grids, producer of the OLTC family named VUC, guarantees 30 years of lifetime. Such a pledge requires high standard devices. This thesis has analyzed data from routine tests of switching times in the diverter switch of OLTC’s, performed before devices were put in service. The correlation of part switching times for all units leaving the factory during the past year was evaluated by calculating Pearson’s correlation coefficient. A linear trend was fitted to the data, realizing that the prediction errors, as well as the part switching times, were Gaussian distributed. The time while the resistor vacuum interrupter was open could be predicted within the interval of approximately 2ms with 2 standard deviations accuracy. To classify time series from the routine test as expected or unexpected, a model-based algorithm was implemented. The average switching time for all consecutive switches was used to define expected series. A moving average was implemented to neglect outliers and remove oscillating patterns. The majority of all data was classified as expected time series. The ones who did not, still preserved a good correlation between the part switching times. Examining the relationship between part switching times could be a valuable perspective in further classification of expected time series. The possibility of incorporating measurement of part switching times on OLTC’s in normal operation, to use the knowledge gained by this thesis, was investigated. Position sensors were mounted to measure the position of the lifting yokes, opening and closing the vacuum interrupters. The time while the vacuum interrupter contacts were open could be estimated with better accuracy than the position sensor provided. Unfortunately, those sensors cannot be utilized in normal operation. If other possibilities could be found, perhaps a laser position sensor, the implemented algorithm would be valuable.