Historically transformers with system earth equipment have been modeled as open circuits in zero sequence. This approximation has been satisfying, but lately it has been discovered that equipment on one side of the transformer have responded to faults that occurred at the other side. Most of these problems took place when the majority of the system on the secondary side of the transformer contained cables. These findings have led to questioning whether or not the former model of the transformer in zero sequence is correct. This report investigates if it is necessary to represent the transformer in zero sequence in another way than it is usually done today.

Bakom uppsatsen finns ett genuint intresse för kartmedier samt funderingen om kartan genomgår en evolution till att bli ett digitalt och interaktivt medium. I aktuella styrdokument för gymnasiegeogra-fin framgår att såväl kartor som GIS skall finnas med i undervisningen, motiveringen är dock bristfäl-lig. I syftet väcktes därför frågor om vilka belägg som fanns för digitala undervisningsmetoder inom geografi? Syftet kondenserades till frågeställningarna: Vad skrivs i litteraturen om digitalt lärande i geografi i allmänhet? Vad skrivs i litteraturen om att använda digitala kartor och programmet Google Earth i undervisningen i synnerhet? Hur svenska geografilärare ser på samt i vilken omfattning de använder digitala kartmedier? För att besvara frågorna genomfördes en litteraturstudie samt en en-kätundersökning. Litteraturstudieresultatet visade främst två saker.

Bakom uppsatsen finns ett genuint intresse för kartmedier samt funderingen om kartan genomgår en evolution till att bli ett digitalt och interaktivt medium. I aktuella styrdokument för gymnasiegeografin framgår att såväl kartor som GIS skall finnas med i undervisningen, motiveringen är dock bristfällig. I syftet väcktes därför frågor om vilka belägg som fanns för digitala undervisningsmetoder inom geografi? Syftet kondenserades till frågeställningarna: Vad skrivs i litteraturen om digitalt lärande i geografi i allmänhet? Vad skrivs i litteraturen om att använda digitala kartor och programmet Google Earth i undervisningen i synnerhet? Hur svenska geografilärare ser på samt i vilken omfattning de använder digitala kartmedier? För att besvara frågorna genomfördes en litteraturstudie samt en enkätundersökning. Litteraturstudieresultatet visade främst två saker.

Aniara is a versified epos written by Harry Martinson in 1956. The story is about a large group of people who are being evacuated from earth to Mars because the earth is radiated. However something goes wrong. They fall out of course and end up on a never ending journey in space.This essay examines the relations between the eposAniara and Lars Rudolfssons dramatization for Stockholm City Theater, played during the fall/winter of 2010. Through performativity and narrative theories I analyze narrations and characterization in the text and in the play.

Uppsatsens syfte är att argumentera för ett verklighetsbaserat lärande inom geografiämnet för årskurs 5. Som ett pedagogiskt verktyg för detta ändamål prövar och diskuterar jag sökmotorn Google Earth (GE) och visar genom 4 exempel hur man kan använda detta verktyg. Jag prövar också GE:s lämplighet i förhållande till de tre ämnesfälten kartografi, fördelning och hållbar utveckling genom att formulera tre lektionsförslag. Jag gör också en kritisk granskning av aktuell forskning kring läromedel och ställer detta mot texter hämtade från kursplanen i Geografi. I min analys når jag fram till att fördelarna med att använda sig av GE i förhållande till traditionella läromedel är främst att eleverna på ett naturligt sätt kommer i kontakt med autentiska och aktuella problemfält som rör vår jord.

The purpose of this project is to analyze earthing systems for houses. By practical measurements and theoretical analyzes consequences of possible faults, that can occur within the facility and in the low-voltage distribution network, is illustrated.  The reason for this project is that nowadays one has to arrange with a main equipotential bonding system for buildings. Apart from that, if necessary, bathrooms must be provided with a supplementary equipotential bonding system.The practical measurements verify that potential differences in facilities may be due to voltage drops in the PEN conductor between the origin of the electrical installation and the power transformer.Based on the theoretical analyzes of possible faults, it is considered that the requirement for  supplementary equipotential bonding systems for bathrooms in most cases can be questioned, when basic insulation, fault protection, residual current devise and main equipotential bonding system already provides an adequate level of protection.A PEN conductor loss may result in a situation where metallic parts attached to the equipotential bonding system starts working as earth electrodes. Equipotential bonding system may also increase the incidence of stray currents. If TN-C-S systems is provided with a local connection to earth a redundant system against PEN conductor loss is obtained.

The thermal response of a borehole field is often described by non?dimensional response factors called gfunctions.The g?function was firstly generated as a numerical solution based on SBM (Superposition BoreholeModel). An analytical approach, the FLS (Finite Line Source), is also accepted for generating the g?function. In thiswork the potential to numerically produce g?functions is studied for circular borehole fields using the commercialsoftware COMSOL.

The subject-matter of the following essay is to investigate the relationship between what is commonly called Deep Ecology or Biocentric Philosophy, as articulated by the co-founder of the Deep Ecology Movement, Arne Naess, and later proponents of the biocentric school of environmentalist thought. I contrast Naess? concept of Self-realization as founded in his Ecosophy T to the ideas of american conservationist and co-founder of the radical green movement Earth First! Dave Foreman, and to the controversial finnish environmentalist and ecofascist Pentti Linkola?s ideological agenda of population-reduction respectively.According to some critics of the movement, especially the social ecologist Murray Bookchin and French liberal philosopher Luc Ferry, the Deep Ecology ideology is essentially misanthropic and totalitarian in structure. A central idea among deep ecologists is that ecosystems and natural entities have intrinsic value in themselves, even outside a human social context. This idea is thought of among deep ecologists to create a philosophically sound basis for counteracting the environmental global crisis.

AbstractThe purpose of this study is to find out how pupils give expression of a water cycle model and if the model causes any misunderstanding. Two problems constitute the starting point for this investigation. The first question is: how do the pupils explain the water cycle with the help of the jar model (can of glass). The other question is: can the children see any similarities between the can of glass and our earth. Qualitative semi structured interviews with seven pupils in the ages of 8-9 have been used to show the pupils? own thoughts and how they express them.

På senare år har etableringen av 3D-applikationer på internet, för att visualisera geografiska områden och platser blivit allt vanligare. Exempel på sådana applikationer är tjänsterna Google Earth och Street View, som levereras av företaget Google. Den snabba utvecklingen av 3D-tjänsterna har medfört bättre bildupplösning och mer detaljerade satellitbilder. Detta har i sin tur fört med sig att integritets- och säkerhetsrelaterade frågeställningar relaterade till 3D-applikationerna har aktualiserats. Från flera håll i världen har Google stött på ifrågasättanden och protester.

The majority of all power cuts that affects individuals and communities are caused by earth faults on the power transmission lines at 10kV and 20kV level [1]. If these power cuts could be eliminated, less disturbances and interrupts would lead to large amounts of money savings.Swedish Neutral has developed such a protection system. When an earth fault occurs power is injected into the neutral point of the transformer. The RCC (Residual Current Compensation) protection calculates a compensation current exactly 180 degrees out of phase to the fault current. Doing this, the voltage at the fault location becomes very close to zero, without affecting the power transmission.The protection system can only compensate automatically for the fundamental frequency (50Hz), and manually for the 3rd, 5th, 7th and 9th harmonics.

This report is written in the purpose to investigate the mechanical forces and characteristics related to a propeller driven aircraft in the Earth?s atmosphere. It?s written as a thesis project during the spring semester of 2014 and graded accordingly.Thanks Arne Karlsson for fruitful discussions. Also thanks to Simon Leijonmarck for help with useful discussions concerning structural batteries..

The world is in a stage of climate crisis where the average temperature is rising, with consequences such as, melting ice sheets, increasing sea levels, and floods. The climate panel of the UN, IPCC, has stated that this is a reaction of anthropogenic emissions of greenhouse gases. The most important gas is carbon dioxide, which contributes with 80 per cent to the on going climate crisis.The increasing emissions of carbon dioxide are connected to human consumption patterns. This puts pressure on the earth, as humans demand more and more resources. Today the earth needs one and a half year to regenerate the resources humans? demand of it, by the year 2030 we will need two planets in order to cope with this increasing demand of resources.At a global level it is established that richer countries have a stronger consumption pattern than poorer, and thus generate higher levels of carbon dioxide emissions.

Considering water quality, landuse and reducion of wetland area in the watershed of Tidan, areas witch are in need of constructions to improve the water quality are identified. Constructions are suggested to be located within the smaller streams in the watershed, so that the water is treated before it reaches the stream Tidan..

Climate on earth is getting warmer, which effects earth?s energy balance and so forth the ocean and atmospheric circulation.  In many sub-polar regions on the northern hemisphere changes due to warming of the climate can be observed. Some examples that already have been observed are shifts in tree line, towards higher altitudes and latitudes, increased ablation of Swedish glaciers and melting of the permafrost on the Siberian tundra. In Sweden climate change scenarios tell us that it will become warmer and that a higher amount of precipitation in form of rain will be an effect from this. To study climate changes in Sweden, transition zones are useful in order to observe changes in distribution of species and animal populations.