Göteborg Energi AB är ett bolag med höga ambitioner att säkerställa ett stabilt distributionsnät för sina kunder. Med ett säkerställande följer åtgärder i form av beräkningar för komponenter som transformatorer av olika märkeffekt, hög- och lågspänningssäkringar och andra kritiska skyddsanordningar som t.ex. reläskydd. Vid ett flertal tillfällen under de senaste åren har det uppmärksammats en problematik där ett fel i lågspänningsnätet har löst ut anslutande transformator. Felet har grundat sig en svag selektivitet mellan transformatorsäkring och lågspänningssäkring.

In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured.

Göteborg Energi AB är ett bolag med höga ambitioner att säkerställa ett stabilt distributionsnät för sina kunder. Med ett säkerställande följer åtgärder i form av beräkningar för komponenter som transformatorer av olika märkeffekt, hög- och lågspänningssäkringar och andra kritiska skyddsanordningar som t.ex. reläskydd. Vid ett flertal tillfällen under de senaste åren har det uppmärksammats en problematik där ett fel i lågspänningsnätet har löst ut anslutande transformator. Felet har grundat sig en svag selektivitet mellan transformatorsäkring och lågspänningssäkring.

Mechanical relays are more and more being replaced with semiconductortechnology. In this thesis it is investigated if and how the larger loads couldbe controlled by transistors. The main part of this work aims to create andverify a solution that can control the starter motor, as well as protect it incase of any failure. The different malfunctions that the solution protectsagainst is high current, too high peak current, low current, maximum cranktime and minimum cool off time. The timers also protect indirectly againstoverheating of the starter engine.The transistors used are BTS555, from Infineon.

Åmotfors Bruk AB (ÅBAB) has today an inefficient production of steam for the manufacturing of paper. Unpredictable energy prices and modernisation of the current equipment has been the underlying factors to invest in a thermal power plant, mainly driven by garbage. This facility will not only use the steam for paper production, it will also generate electricity through a steam turbine. Today, when a fault on the supplying line occurs which leads to disconnection of the external grid, all the support of electricity to Åmotfors Bruk (ÅB) will disappear. This will lead to major interruptions in the paper production, which will cause severe economical losses.

This report deals with RFID systems and how to detect nearby tags with the Mifare standard using only a microcontroller and an antenna circuit.The aim was to investigate whether there was any possibility to continuously search for a nearby tag for a system operated with batteries without compromising   the lifespan of the battery. At this time the system would take too long time to wake up and look for a tag to give a satisfactory battery lifespan, which should be done a couple of times every second.The report has two issues, namely:Is it possible to direct the microprocessor to detect and identify a nearby tag after the Mifare standard?What hardware is required for this to be possible?As the research method to provide answers to the above questions an action research was used. This approach has meant that the group worked on information retrieval, examined existing solutions, tested their own solutions and documented the results.The group examined an existing solution that can search for nearby tags with minimal energy consumption. An antenna circuit was built that was connected to the processor.

I have always lived around mines and around people work­ing with mines. They are a natural part of my life and, inev­itably, a great interest of mine. When time came to make a decision for a degree project, focusing on the mine context felt as natural as breathing.In LKABs underground mines, safety in fire accidents is a great priority. Of outmost importance for the escape is to have a personal gas filter for filtration of smoke and/or gas. My design project resulted in a concept which is aimed at shortening the user journey from the start of the accident until the user has applied the personal safety solution and is ready to escape.Throughout the project I?ve been working with a context which is heavily regulated, and all problems are serious, important ones.

SAAB Aerotech division FGR in Arboga builds and develops equipment and components used in both military and civilian applications. To build a test system for a specific project that SAAB is responsible for requires a simple signal generator that can provide a pulse modulated signal. The need to buy a new advanced signal generator for example from Agilent is not as profitable as the instrument is expensive and contains features that SAAB does not require in their applications and test systems. That was the reason why SAAB offers two students a thesis where the goal is to construct a signal generator in accordance with what SAAB requests.This thesis contains several different phases. The first step was a meeting with our supervisor Mats Bergman and by reading the data sheets for components to be used in the project, with these information and specifications that we have received from SAAB we started to construct the signal generator.What we did during the construction work was to simulate and draw a schematic to be able to design the circuit board.

This thesis is about developing a design that provides improved vacuum seal between a lead coating and a plastic coating during plastic extrusion processes of cables. This report is a part of the course MSGC 17 for Bachelor Engineers in mechanical engineering.The work is performed at Nexans Norway AS in Halden where they have a production of high voltage cables for sea-, and offshore industry. A problem they face is that they do not get enough good seal at the attachment to the plastic extrusion machine. They want to achieve a vacuum between a lead coating on the cable and a plastic coating of the cable for plastic extrusion, which is something they do not achieve today. The thesis is thus to come up with a design that provides better sealing against the cable.The work involves a construction part with the phases of product development processes.

The purpose of this master thesis is to construct a steering transmission, for a trackedvehicle, containing two hydraulic circuits which are connected. The steeringtransmission should be mechanical to avoid steer-by-wire.BAE Systems Hägglunds has in an earlier study examined a system with two hydraulicpumps and one hydraulic motor, but the safety of the system wasn?t sufficient.To achieve sufficient redundancy there must be two hydraulic motors, which arecontrolled separately. When the two systems are connected in one point, this point is acritical part of the system because it directly affects both circuits. If one of the hydrauliccircuits fails the other should be able to operate independently as a steeringtransmission.

Transmission of reactive power is well known to cause active power losses. Thus, newcomponents who can help minimizing these expensive reactive power flows are ofgreat interest to the power distribution companies. ABB Corporate Research hasdeveloped the first electronic power breaker. One possible application for thisbreaker is transient-free switching of capacitor banks. This could prove a usefuldistribution voltage complement to the switch-sync technique, mainly applied to transmissionvoltage level.

The current study sought to examine if post-produced semantic memory cues are a good aid for memory recall. It also focused on remembering units with a meaning, instead of just remembering lists of words. In the current study a factual text was used where the participants were tasked with recalling as much information as possible either with the aid of cues (keywords written by the participants themselfs), computer with Internet or no aids at all. The results showed that keywords are significantly better for memory recall. The results were discussed in regards to modern models describing semantic memory.

I följande uppsats jämförs bilden av "Sverige ? det nya matlandet" mellan Jordbruksverket och VisitSweden och hurvida den överensstämmer eller ej. Det empiriska materialet är baserat på rapporter, pressmeddelanden och andra webb publikationer. Materialet analyseras sedan enligt en diskursanalys. Vi fann att bilden skiljer sig mellan de två aktörerna..

The government regulations for energy use in buildings will be tightened in the future. At the same time the interest in environmental classifications and certifications of buildings is increasing. This has meant a new situation for solar energy. The designs of solar heating systems are often based on experience and/or rules of thumb, rather than calculations and simulations. This thesis examines whether simulation tools, in this case Polysun, are useful in this work.

The government regulations for energy use in buildings will be tightened in the future. At the same time the interest in environmental classifications and certifications of buildings is increasing. This has meant a new situation for solar energy. The designs of solar heating systems are often based on experience and/or rules of thumb, rather than calculations and simulations. This thesis examines whether simulation tools, in this case Polysun, are useful in this work.