Theme of this master's thesis Comparison of thermal cycle efficiency is aimed on the calculation of thermal schemes of reheating and without reheating for various performances. The calculation is performed using specialized literature. The introduction describes the fundamental thermal cycle used in power plants and Rankine - Clausius cycle. After the initial familiarization with the parameters of Rankine - Clausius cycle follow a section with technical solutions to improve thermal efficiency of Rankine - Clausius thermal cycle. The aim of this work is to identify and compare the thermal efficiency of the thermal cycle with reheating, without reheating and compare them with each other. At the conclusion of this work is shown comparison between two low-pressure regeneration systems.

Dagens linjära materialflöde leder till att nyttjandegraden av råvaror är låg, vilket tömmer ut världens resurser och mängden avfall ökar. Samtidigt skapar den ökande världsbefolkningen och världsekonomin ett större tryck på dagens resurser vilket inte är hållbart i längden. Genom att övergå till cirkulär ekonomi betraktas genererat avfall som en resurs, vilket ökar resursutnyttjandet i samhället. Byggbranschen är den verksamhet som genererar mest avfall i Sverige och stor del av den genererade mängden är träavfall. Idag energiutvinns i stort allt trä som kasseras och samtidigt sker ett ökat intresse för användning av materialet. Syftet med denna studie är att ta reda på hur och i vilken mängd träavfall från bygg- och rivningsarbete kan materialåtervinnas före energiutvinning.  Denna studie har kartlagt innehållet av tre containrar med träavfall från olika byggskeden; stomme, inredning och rivning. Kartläggningen utfördes med en sorteringsmetod som togs fram med hjälp av litteraturstudie och samtal med företag. De fyra möjliga sorteringsalternativ som togs fram under studien var Fingerskarvning / Återanvändning, Korslimmat trä, Lamellträ och Spånplattor.  Kartläggningen visar att fördelningen av träavfall varierar stort beroende på byggskede. Vid inredning är det mycket lastpallar, träskivor och reglar, detsamma gäller för stomme dock med en färre andel skivmaterial.   Vid maximal utdelning för stomme kan 19 % av träavfallet gå till Fingerskarvning / Återanvändning, Korslimmat trä  2 %,  Lamellträ 35 % och Spånplattor 100 %. Vid rivning fanns endast treetex och råspont vilket endast kan användas till Spånplattor. För inredning kan 12 % av träavfallet gå till Fingerskarvning / Återanvändning, Korslimmat trä 3 %, Lamellträ 10 % och Spånplattor 100 %. För stomme och inredning är resultatet baserat på en accepterad sortering för grånat och smutsigt virke för de två förstnämnda alternativen. Slutsatsen blir att allt träavfall kan användas till bättre alternativ än energiutvinning. Tills problemen med Korslimmat trä och Fingerskarvning / Återanvändning har lösts bör sortering ske utefter Lamellträ och Spånplattor. / Today's linear material flows leads to a low utilization of raw materials, which depletes the world's resources and the amount of waste increases. At the same time, the growing world population and world economy are creating more pressure on today's resources which is not sustainable in the long run. By converting to a circular economy, generated waste is regarded as a resource, which increases the utilization of resources in society. When it comes to generated waste, the construction industry is the biggest sector in Sweden and wood waste is a large part of the generated amount. Almost all wood waste today is combusted for energy recovery, and at the same time, there is an increased interest in using the material. The purpose of the study is to find out how, and in what amount, wood waste from construction and demolition work can be recycled before energy recovery.  This study has made a survey of the contents of three containers with wood waste from different construction stages; frame, fixing and demolition. The survey was carried out using a sorting method that was developed by studying literature and speaking with companies. The four possible sorting options that were found during the study were Finger jointed / Reuse, Cross-laminated timber, Laminated wood and Particleboard.  The survey shows that the distribution of wood waste varies greatly depending on the stage of construction. In the fixing stage, there are a lot of pallets, wooden boards and studs. The same goes for the frame stage, however, with a smaller proportion of board material. The maximum percentages for each of the sorting options for the frame stage are        19 % to Finger jointed / Reuse, Cross-laminated timber 2 %, Laminated wood 35 % and Particleboard 100 %. During demolition, there were only treetex and tongued and grooved board that can only be used for Particleboard. For the fixing stage, 12 % of the wood waste can go to Finger jointed / Reuse, Cross-laminated timber 3 %, Laminated wood 10 % and Particleboard 100 %. For the frame and fixing stage the results are based on an accepted sorting of gray and dirty wood for the two first mentioned sorting options.  The conclusion is that all wood waste can be used for better alternatives than energy recovery. Until problems with Cross-laminated timber and Finger jointed / Reuse have been solved, sorting should be based on Laminated wood and Particleboard.

No description available.

An 18-month study (July 2009 – December 2010) was conducted to determine the influence of four dams located in series along the Perak River, in Malaysia: Temengor, Bersia, Kenering and Chenderoh dams. The framework for investigation centered around the Serial Discontinuity Concept (SDC) and the Cascading Reservoir Continuum Concept (CRCC). In addition to reservoir, tailwater and riverine reach characteristics, the interacting influences of tributary streams and watersheds were addressed. Variables included in-situ environmental physical parameters, nutrients, seston concentration and transport, and fish assemblage characteristics. In-situ variables, water and seston samples, were recorded/collected monthly from all four reservoirs, their associated riverine sections, and their primary tributaries. Fish samples were collected by using experimental gill nets in reservoirs. Fish were enumerated taxonomically and total length and weight were measured for the bony-lipped barb, Osteochilus hasselti (Valenciennes, 1842). Hypotheses were tested using analyses of variance with permutations. Relationships were determined using correlation, and multivariate and regression analyses. The integrated influences of discontinuity and cascading on nutrient and seston transport dynamics and fish assemblages (except for relative condition and biomass of O. hasselti) were operative in dynamic juxtaposition along the river’s continuum, and depended on distance between dams and presence and size of tributary streams. However, principal tributaries along the four serial dams in the Perak River appeared to have little spatial influence on their respective system’s nutrient and seston dynamics due to dilution effects of mainstem discharges. Among all tributaries, only the Rui River depicted reversal of the serial discontinuity trend in its system. Even so, its influence on its system was limited. Effects of ecosystem fragmentation along the river’s continuum on in-situ, nutrients and seston transport dynamics, and fish assemblages existed, but not necessarily in line with the SDC nor in line with the CRCC. The dynamics of in-situ, nutrient, seston and fish assemblage parameters were more associated with land use, reservoir surface area and dam discharge. Results from this study generated a hypothesis that submerged woody vegetation in the reservoirs may augment and compensate lost nutrients, thereby minimizing functional impacts of serially-arranged dams.

A new approach to the evaluation of the reliability of electrical systems is presented. In this approach a Graph Trace Analysis based approach is applied to integrated system models and reliability analysis. The analysis zones are extended from the traditional power system functional zones. The systems are modeled using containers with iterators, where the iterators manage graph edges and are used to process through the topology of the graph. The analysis provides a means of computationally handling dependent outages and cascading failures. The effects of adverse weather, time-varying loads, equipment age, installation environment, operation conditions are considered. Sequential Monte Carlo simulation is used to evaluate the reliability changes for different system configurations, including distributed generation and transmission lines. Historical weather records and loading are used to update the component failure rates on-the-fly. Simulation results are compared against historical reliability field measurements. Given a large and complex plant to operate, a real-time understanding of the networks and their situational reliability is important to operational decision support. This dissertation also introduces using an Integrated System Model in helping operators to minimize real-time problems. A real-time simulation architecture is described, which predicts where problems may occur, how serious they may be, and what is the possible root cause. / Ph. D.

In 1998 the UN Guiding Principles on Internal Displacement were developed following years of crises faced by the millions of people experiencing forced displacement, especially those internally displaced. These Principles were widely considered to be precedent setting, both historically and normatively. However, the examination of the construction of the international norms that underpin the Principles indicates that there are important epistemological weaknesses in widely used constructivist frameworks that understand normative shifts in international relations. They are critiqued as being impedingly linear, temporally compressed and analytically obstructive in its agent-centric view of norm cascading. This research aims to address some of these gaps with an enhanced life-cycle model using cluster genealogies and the processes of replication and particularization. The reformulated framework is tested for robustness and feasibility using two preliminary cases – UNSC Resolution 1325 and the Chemical Weapons Convention. It is then used to conduct an in-depth original analysis of the development of the 1998 UN Guiding Principles. The findings in the case of the Guiding Principles show, for example, that though the acceptance of the IDP definition was a big leap, the replication and particularization of human rights limits the humanitarian scope of the Guiding Principles, and also brings into question existing humanitarian protection of IDPs under the Geneva Conventions. Meanwhile, rooting them in ‘sovereignty as responsibility’ has not shifted the community of states’ intersubjective take on sovereignty, but it has added to the existing normative tension – individual vs. state – that underpins the very understanding of sovereignty.

Substations are joints in the power system that represent nodes that are vital to stable and reliable operation of the power system. They contrast the rest of the power system in that they are a dense combination of critical components causing all of them to be simultaneously vulnerable to one isolated incident: weather, attack, or other common failure modes. Undoubtedly, the loss of these vital links will have a severe impact to the to the power grid to varying degrees. This work creates a cascading model based on protection system misoperations to estimate system risk from loss-of-substation events in order to assess each substation's criticality. A continuation power flow method is utilized for estimating voltage collapse during cascades. Transient stability is included through the use of a supervised machine learning algorithm called random forests. These forests allow for fast, robust and accurate prediction of transient stability during loss-of-substation initiated cascades. Substation risk indices are incorporated into a preventative optimal power flow (OPF) to reduce the risk of critical substations. This risk-based dispatch represents an easily scalable, robust algorithm for reducing risk associated with substation losses. This new dispatch allows operators to operate at a higher cost operating point for short periods in which substations may likely be lost, such as large weather events, likely attacks, etc. and significantly reduce system risk associated with those losses. System risk is then studied considering the interaction of a power grid utility trying to protect their critical substations under a constrained budget and a potential attacker with insider information on critical substations. This is studied under a zero-sum game theoretic framework in which the utility is trying to confuse the attacker. A model is then developed to analyze how a utility may create a robust strategy of protection that cannot be heavily exploited while taking advantage of any mistakes potential attackers may make. / Ph. D. / Substations are key components to the continued and reliable operation of the power system. Their removal from the power system would severely hinder the system’s ability to transport power from power producers to end consumers. As larger weather events and potential threats to the power system are being considered, power system engineers to start considering the impact that losing substations would cause on the system. This work studies the impact on the system associated with losing substation and ranks them to find the most important ones. A probabilistic model is created based on incorrect operations in power system protection elements that historically have exacerbated large events in the power system. Mitigation of this impact is then studied through two preventative means: changing the operating condition of the current system and adding protection to the substations. This is in order to secure the system before potentially losing the operation of a substation. The operating point change is formulated as a new optimization problem that helps alleviate stress on the system close to the most critical substations found in the earlier model. Protection of these substations is analyzed through game-theoretic means where the utility tries to confuse any potential attackers on which substations actually have true, rigid protection on them. In doing so, on expectation, the damage done to the system may be reduced significantly.

Esta dissertação de mestrado investiga os formatos de modulação óptica alternativos ao tradicional formato binário de intensidade (NRZ - Non-return-to-zero), ditos avançados, como tecnologia chave para atender às exigências do mercado atual de telecomunicações por transporte de grande volume de dados e alta largura de banda, associados com a redução do custo da informação transmitida por bit. Os formatos avançados de modulação óptica fazem parte das tecnologias que estão sendo investigadas intensamente com o objetivo de superar os desafios impostos pela nova geração de sistemas ópticos com taxas a partir de 40 Gb/s. Este trabalho focaliza o estudo dessa tecnologia, apresentando uma visão geral dos formatos mais discutidos atualmente, suas características e tecnologias de implementação. Foram realizadas simulações utilizando o software comercial Optisystem versão 7.0 da empresa canadense Optiwave Systems Inc., para analisar o desempenho de alguns formatos de modulação de intensidade e de fase com respeito à sensibilidade do receptor, resistência ao cascateamento de filtragem óptica e a efeitos dispersivos e não-lineares. Procurou-se avaliar os formatos em enlaces reais, com características necessárias à sua possível utilização. Também é feita uma breve consideração dos custos associados aos formatos de modulação analisados neste trabalho. Dentre os formatos analisados, os RZ (Return-to zero) apresentaram maior sensibilidade do receptor e melhor tolerância aos efeitos não-lineares que os seus equivalentes NRZ, porém baixa tolerância aos efeitos dispersivos e ao cascateamento de filtragem óptica. O formato duobinário mostrou fraco desempenho de sensibilidade, mas provou ser o mais tolerante à dispersão cromática e à concatenação de filtragem óptica. Os formatos de modulação de fase mostraram ser bem resistentes aos efeitos não-lineares e aos efeitos dispersivos. / This MSc thesis investigates optical modulation formats as an alternative to the use of the traditional intensity binary format NRZ (Non-return-to-zero). Those formats, classified as advanced, represent one of the key technologies aimed to enable the high data volume and broadband, demanded by the present telecommunication market, with cost reduction of transmitted information per bit. Those technologies have been intensevely studied with purpose of overcoming the challenges imposed by the new generation of optical systems, with bit rates from 40 Gb/s. This work focuses on the study of modulation formats most discussed currently, presenting an overview of their main characteristics and implementation techniques. The performance of some intensity and phase formats, in terms of receiver sensitivity, optical filtering cascading, dispersion and nonlinear effects robustness, have been theoretically analyzed from simulations carried out with the commercial software Optisystem v. 7.0, of the Canadian company Optiwave Systems Inc. The analysis has been applied to real optical links, with characteristics that, potentially, demand their use. A cost analysis, based on estimated values associated to devices required for implementing the formats investigated in this work, is also presented. Among the formats studied, those based on RZ (Return-to zero) presented the highest receiver sensitivity and best tolerance to nonlinear effects, in comparison to their equivalent formats, based on NRZ. However, they are less tolerant to dispersive effects and optical filtering cascading. The duobinary format (DB) has shown a weak performance in terms of sensitivity, though has been proved to be the most tolerant to chromatic dispersion and filtering cascading effects. Among all formats, the phase modulation ones presented the highest resistance against nonlinear and dispersive effects.

於歷史事件中我們知道電力網路中些許的傷害會導致大停電事件的發生，而電力網路的安全是學者們一直以來關心的議題，複雜網路發展至今，已有不少研究人員利用複雜網路的方法來分析電力網路，本論文即利用複雜網路的分析方法，分析台灣電力網路脆弱性，並提出一新穎的保護策略。 文章中引用三種分析方法分析台灣電力網路的脆弱性，第一為根據網路效率(efficiency of complex network)，第二為根據靜態負載的連鎖性失效(static load cascading failure)，第三為根據動態負載的連鎖性失效(dynamic load cascading failure)，三種脆弱性分析的方法得到結果的交集處，在文中被認為是電力網路中最具風險的變電站。根據靜態負載的連鎖性失效的結果，我們在不改變網路結構和整體網路的負載量之下，提出一新穎的安全策略，試圖降低靜態負載時連鎖性失效帶來的傷害，並分析此安全策應用至ER隨機網路(ER random network)、BA無尺度網路(BA scale-free network)和台灣電力網路，且量化其結果。 三種脆弱分析的結果皆有共通的部份，表示台灣電力網路在拓樸分析下並不堅固，其結果顯示此安全策略是有效的。本篇論文分析的網路均是無權重也無方向性的網路，如此，未來在網路脆弱性與安全策略的研究還有進一步的研究空間。 / From blackout events in history, we know the damage of a few substations or transmission lines can lead to a big blackout, and the robustness of power grids are always a great concern. Recently the topological analyses of power grid network have developed rapidly and its achievements have become a center of attention. This thesis aims to investigate the vulnerability of Taiwan’s power grid through topological analyses and propose a novel protection strategy. This thesis introduces three methods to investigate the vulnerability of Taiwan’s power grid. The first method is based on efficiency of complex network. The second method is based on static load cascading failure. The third method is based on dynamic load cascading failure. The common results of the three results are considered the high risks in Taiwan’s power grid. According to the static load cascading failure, we propose a protection strategy against cascading failure without changing the structure of network and the whole load of the network, and then demonstrate the effectiveness of this strategy on an ER random network, a BA scale-free network and Taiwan’s power grid numerically. The three methods having the common results, one may say Taiwan’s power grid isn’t robust under the topological analyses, and our protection strategy may be useful for decreasing the damage after cascading failure.

現實社會中，有時會發生大規模的停電事件，一經調查後才瞭解，只是因為一根電纜線、一根高壓電塔或是一個變電站故障導致，令人好奇電力系統的運作模式。因此藉由拓蹼網路的特性去研究電力系統的安全性及穩定性，一直受到人們的關注和討論。本篇論文利用動態負載去模擬現實中的電流，並藉由連鎖性失效的攻擊策略對於網路效率的影響，去判斷其網路的脆弱性分析。 本論文利用網路效率的(efficiency)影響來作為網路脆弱性(vulnerability)的分析，藉由在靜態負載中連鎖性失效的模型(static load cascading failure model)和動態負載中連鎖性失效的模型(dynamic load cascading failure model)來判斷及討論，其中動態負載為不同發電量及消耗量的狀況，藉此觀察台灣的電力網路系統在狀況下的結果。 此外以攻擊方來思考，單一攻擊、多重攻擊和策略性的多重攻擊的狀況底下，網路效率的變化，並將此運用在台灣電力網路系統上，發現台灣電力網路相當脆弱。 / In the real world, sometimes there will be black out (power shortage) happening in large scale areas. After investigating, we found out that it was cause by either a broken transmission line, a high-voltage tower or a substation. We are very interesting to know how the operation scheme of power system works. Therefore, we study the safety and the stability in power system by the characteristics of topology network. This subject is always concerned and discussed by the society. The thesis use dynamic load to simulate current in real world. We foc us effect on network efficiency by the strategy of cascading failure, analyze the vulnerability of network. The thesis use the variation of network efficiency as index to analyze network. According to determining and discussing by static load cascading failure model and dynamic load cascading failure model, dynamic load is the situation in different amount of generating and consumption of electrical energy. We used the data to observe the result of Taiwan power system under the situation. In addition to, changing of internet efficiency by single attack, multi-attack and strategic multi-attack in attacker method of thinking. We found that Taiwan power system is weak after we used the statistics on it.