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11215 Uppsatser om Stand-alone power system - Sida 8 av 748
Det talas om utbrändhet : vilken roll spelar maktstrukturen
In this paper we investigate whether power structures in organizations have an influence in the process that leads to burnout. We analyze if these power structures affect the individual?s health condition toward burnout in a way that leads to disability and subsequent absence from work. In the study, six persons who all have been unable to work due to burnout have been studied through qualitative, semi-structured interviews. The material have been coded with three different themes; leadership and hierarchy, responsibility and delegation of responsibility and performance and loyalty.
Optimering av ett småskaligtvattenkraftsystem
This master thesis covers the seasonal planning of a small scale hydropower system. The system in this study is owned and operated by Mälarenergi Vattenkraft AB. The total system consists of 4 different main rivers with 24 hydropower stations and several dams. The total installed power in the system is 43.75 MW. Most of the hydropower stations are regarded as small scale hydropower stations and thus entitled to green certificates.In this report the issue of planning is formulated as an optimization problem.
Analys av designalternativ för snabbare dynamik i kolkraftverk med koldioxidavskiljning
Combustion of fossil fuels is today the dominating source of energy. During combustion,carbon dioxide is formed. The carbon dioxide accumulates in the atmosphere,which raises the global average temperature on earth through the so called greenhouseeffect. The only way to reduce the emissions of carbon dioxide from combustionin a coal fired power plant is through carbon capture and storage (CCS).Post-combustion capture is a technology to separate carbon dioxide from the uegas after the combustion for efficient transport and storage. The steady state operationof coal fired power plants with post combustion capture has already beenthoroughly investigated on a pilot scale, however much work remains to investigatethe plants dynamic operation.
Vetenskap och makt. En analys av två vetenskapliga paradigms skilda maktlogiker.
This essay analyse the relationships between scientific paradigms and different logics of power in the field of psychiatry, primarily in the fields of attention disorders of children and schizophrenia. In these two fields of psychiatric research and treatment, there exist two scientific paradigms, a biological/neuropsychiatric and a socialpsychological, working from different standpoints regarding questions of ontology, epistemology and theories of value. Drawing from Thomas Kuhns paradigmatic theory of science, and Michel Foucaults concept of power, this essay proposes that different paradigmatic standpoints gives rise to different logics of power. Relying on the concept of power/knowledge and different paradigmatic standpoints, the essay states that the biological/neuropsychiatric paradigm produces a biological individualising logic of power that fixes the individual to his/hers biological condition. This in contrast to the socialpsychological paradigm, which on the basis of its paradigmatic standpoints produces a social-group related logic of power.
Implementering av en PSS i Trängslets kraftstation
The purpose of this master thesis is to implement and validate a Power System Stabilizer (PSS) to a generator at Trängslet hydropower station in Dalarna, Sweden. Problems with local rotor oscillations can occur at the hydropower station when power is transferred on a new power line (130 kV) from Northern to Southern part of Dalarna. To ensure good operation properties on this power line Fortum Generation AB and Fortum Distribution AB wants to activate a PSS on a generator.There have been investigations in which situations and what equipment that contributes to rotor oscillations. When this is known the PSS is tuned to damp these oscillations by choosing a good set of parameters. The most important parameters for good performance are to choose amount of gain and phase compensation.
Ny teknik för småskalig kraftvärme : - med fokus på Organisk RankineCykel (ORC)
As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique.
Säsongsvis avverkning : det operativa traktvalets påverkan på den säsongsmässiga uthålligheten i ett bolagsdistrikts traktbank
Due to soft grounds in combination with seasonal variation in soil humidity, there is a lack of stands that are possible to cut during spring and autumn in some geographical regions. For Holmen Skog this sometimes means that a large proportion of the contracted private forest is cut during the winter when the ground is frozen. One consequence of this is that the proportion of winter stands in the stand bank of own forest increases while spring and autumn stands becomes a scarcity. This in combination with milder winters, especially when there is a long period of reduced bearing capacity in spring or autumn, means that the situation rapidly can become critical.
The overall goal with this study was to generate basic data for decision support in the work to achieve a sustainable distribution between own forest and contracted private forest in the stand bank.
The study took place at Holmen Skog, district of Umeå, during autumn 2007 and was based on interviews and an analysis of harvest planning and delivery data.
The study showed that there is a problem with how the cutting is distributed between own and contracted private forest during the year and that it foremost is the proportion of winter thinning of own forest that has increased in the stand bank.
Vad räknas som mjuk balansering? Om Venezuelas ambitioner att minska amerikanskt inflytande
This thesis deals with the concept of soft balancing, traditionally defined as the diplomatic means of restraining a dominant state's ability to exercise its military power. As the dominant power in today's unipolar system, the United States, and other states? behaviour towards it, is the focus of analysis. The aim of this thesis is to explore the possibilities of developing the concept of soft balancing so as to include strategies to restrain also the political and economic capabilities of a dominant power. The thesis also considers the possibilities of soft balancing that small states ? to a large extent overlooked in existing theories on the subject - can possess.As a state with policies that aim to reduce the U.S.
Överföring av och beräkning med timmätta värden ? från MT2000 till Xpower
New technology makes it possible to remotely measure all consumers in a power network onan hourly basis and store the values in a database.This thesis work describes the conversion process between automatic meter reading systemMActor and calculation software Xpower.Then the possible differences between calculations of power networks using load curves incombination with a yearly estimate of consumption and calculations using hourly measuredvalues is examined.The result of the comparison shows that, for the power network under inspection, nosignificant difference could be noticed. This does not mean that calculations using hourlymeasured values would be unnecessary. I believe that in a near future calculations using hourmeasurements will be the primary choice for many power companies to whom technology isavailable.Also some basic calculations of fundamental power network parameters, such as power factorand loses, are presented using hourly measured distribution transformers in combinations withits hourly measured loads.The report is written in Swedish.
Effektiviseringspotential inom industrisektorn : Energibesparing vid frekvensstyrning av centrifugalpumpar ? en fallstudie
The project was performed at SiemensIndustry Drive Technologies with theobjective to provide actual values forthe energy savings potential withinSiemens scope of practice.In Sweden the electrical drives standfor about 30 % of the total electricityconsumption and about 60 % of theelectricity consumption within theindustry. During the pre-study phaseelectrical drives with pump applicationswere identified as large energy users.Because of this a case study at one ofSiemens customers, Stora Enso Fors wasperformed. The system that was evaluatedduring the case study was a throttledsystem with a centrifugal pump forpumping pulp.The results yielded that a saving ofover 50 % could be achieved by replacingthe throttle valve with a variable speeddrive, a frequency converter. Thepayback period was two years and twomonths and the present value for thetotal life cycle cost of the variablespeed system was 662.566 SEK lower thanfor the throttled system. As aconsequence, Stora Enso Fors is advisedto invest in a frequency converter forregulation of the system.The general conclusion is that a focuson system efficiency is the mostimportant factor in energy efficiencyprojects and that the system regulationmethod has a large impact on the overallsystem losses and hence its efficiency.Energy efficiency potential forthrottled systems with centrifugal pumpsis large and significant economicalsavings can be made through investmentswith short payback time..
Den spruckna metallen : En psykoanalytisk läsning av Karin Boyes roman Kris
Karin Boyes Crisis (Kris) was published in 1934 as a contribution to the contemporary ideas of moral issues, challenging the dominating traditionalism within the literature critisism.With different kinds of stylistic procedures is Crises expressing a self which seeks to relieve itself from the repressing experience of Language. The text shows an attempt to create meaning beyond the conventional system of linguistic signs, beyond the tradition of literature.The focus in the essay is the self; the self is the basic structure and the theme of the text. Crisis shows it?s self-assuredness and points out a dialogue with the nietzschean philosophy. Nietzsche claims that the truth is a rhetorical creation, something which the language produces in the will of power.
Hybridlärkens tillväxt i Snogeholm : hur påverkas produktionen i blandbestånd jämfört med trädslagsrena bestånd?
The hybrid larch (Larix x eurolepis Henry) is a fast growing tree species and was introduced in Sweden for about 50 years ago. The high growth and expected resistance to diseases are probably the main reasons of introducing the tree species into the Swedish forests.
The purpose of this thesis was to document the production of hybrid larch planted in the Snogeholm landscape laboratory and to compare the production in the pure hybrid larch stand with the mixture together with pedunculate oak (Quercus robur).
The data collection in Snogeholm since the establishment has been carried out by the Swedish University of Agricultural Science (SLU). The fieldwork for the thesis was carried out in 3 stands, containing hybrid larch, pedunculate oak and a mixture of hybrid larch and pedunculate oak, in order to be able to compare the total stand production of the areas.
The results show that the total production of hybrid larch in the mixed stand only is 35 % compared with the total production of hybrid larch in the pure stand. Therefore, the hypothesis that the total production of hybrid larch is equal to the planted mixture with pedunculate oak was rejected.
The other hypothesis that the total production of a 2 hectare large stand containing a mixture of hybrid larch and pedunculate oak would be greater than the total production of two pure stands of 1 hectare containing hybrid larch and oak each was also rejected. In the studied case the total production was 45 % greater if hybrid larch and pedunculate oak was planted in pure stands.
The results from the case-study only indicate that the total production of hybrid larch and oak under the investigated conditions can be higher when planting the two species in pure stands compared with a mixture of the two species.
EMC problematik och el-kvalitet i elkraftnät
The dissertation deals with an account of actual problem, which can arise within EMC and power quality. The cause of power interruption and what can be done to minimise the power interruption is discussed. It also includes a definition of planning levels and which factors one needs to have control over to carry out a possible planning strategy and how the local distributions net could be more secure. The electrical net could be secure but no system can be free from interruption.The dissertation examines two distribution transformers: GLA40T1 (Glansås) and T399 in Tranås Energy which don?t have regulators.
Statuskontroll av Paradisskolans elektriska belastning
In this thesis is studied the electrical load of Paradisskolan with respect to power quality and energy consumption. The school's owner Trollhättans Tomt AB is also interested to know if they can reduce their costs by changing to smaller meter fuses. A recurring ground fault that?s been recorded from powerpanel A1A has been investigated. The school's equipped with an electrical bonding system, harmonic filters for the third harmonic currents, TN-S system from feeding transformer and groundfault monitoring.
Digital delaktighet i Sverige : Om att inkludera alla i framtidens samhälle
Almost all Swedes today have access to the Internet, if not through the home then via the library or work. Despite this, around 20% of the population stand outside the information society in that they lack in knowledge, assistive usability tools or positive attitude towards technology and its influence on society. The main factors influencing the digital divide in today's society are age, disability and education, while the main reason for staying outside seems to be disinterest.The question about digital inclusion is important as we now stand on the breaking-point between a society where the industry has had a prominent position for private as well as national economy and a digital society where access to the Internet is no longer about prestige, but where significant differences between users' knowledge levels can create a power gap. Gaps in access and use not only reflects already existing socio-economic conditions, but can also maintain and enhance these.It is crucial for the future expansion of Internet usage how today's non-users feel about becoming users. To understand what underlies the motivations not to use computers is one of the keys to get non-users to embrace becoming users.