Gravitational lenses are unlike ordinary optical lenses, a phenomenon corrupting our optical view of the cosmos. When we look out intospace we see celestial bodies lying with astronomical distance from Earth. There is no guarantee that what we see out there in space is actually there where we are observing it, and it may be that we see multiple images of the same star! Studies have shown that thenumber of distorted images of an n-mass (n > 1) plane lens can not exceed 5(n -1) for lighter lenses or 5n for more massive lens. This mathematical thesis covers gravitational lensing and their properties that distort light rays coming towards us from distant celestial bodies. In addition of gravitational lensing, its properties and the proof of the maximum number of distorted images, a bigger part of this work even cover two very interesting mathematical tools - the so-called Schwarz function and Bezout theorem..

In relation to the development of IT-products it is very important that the software supplier is aware not only of the target group but also the field of application. Usability should characterize the whole IT-design process as, in relation to this context, design includes more than merely those aspects which are visible to and thus can be interpreted by the naked eye. The study examines the specific qualities and properties that substantiate the usability and the demands that a customer rightfully expects from an IT-product. The user and the customer are highlighted in the same context in order to demonstrate that it is through the customer that an IT-product is defined as being useful. Thus, from this perspective, the user and customer can be considered as being the same person.

Background: Suicidal patients feelings and experiences of the psychiatric service can be a decisive moment of the following treatment. Although suicide is a common problem all over the world we know very little about the feelings that the patients are feeling in residential psychiatric care. Purpose: The aim of this litterature studie was to describe suicidal patients feelings and experiences of the psychiatric service. Method: Literature study was conducted through a search of articles in different databases. The data has been done as an overview and the data has been analysed with content analysis.

In Sweden, large scale planting of Lodgepole pine (Pinus contorta var. latifolia) started in the beginning of the 1970?s. At first, the aim was production of pulpwood, but later, also production of timber became considered realistic. Today, Sweden has more than 520 000 ha of Lodgepole pine.

This study is a degree project in environmental engineering at Mälardalens university. Its purpose has been to perform a risk assessment on whether or not any contaminations are present in the soil at two properties in Köping. The assessment was to be done accordingly to a method that has been set up by The Swedish Environmental Protection Agency (Naturvårdsverket). The method for investigation of contaminated sites is called MIFO. MIFO consists of two stages.

The main purpose of this study is to investigate the needs of pre-commercial thinning on private owned forest properties, which is considered to be increasing. The reason is believed to be the high cost of labor that pre-commercial thinning brings. Furthermore thinning is costly, the revenue created through pre-commercial thinning are post-poned until the first thinning. The study was made through a survey among members of Mellanskog forest owners association. The survey was distributed by e-mail. The time to answer was set to two weeks. The answers indicate that the most common reason why the pre-commercial thinning is delayed, or not done at all, is the forest owner?s lack of time.

The purpose of this study was to examine how some young mothers, who previously have been in foster care or residential care, describe the way motherhood has affected their lives and identities. Narrative interviews were conducted with three teenage mothers and one mother aged 23. As tools for analyzing the narratives, theories about narrative psychology and how people present themselves through story-telling and language were used. The results of the study show that becoming a mother was life-changing in a positive way, according to the young mothers. They described how they, since becoming mothers, had become more mature and now lived less risk-full lives.

The study Packning i tid och rum (Crowding in Time and Space) is a Master Thesis in Human Geography within Geography, presented at Södertörn University College.The aim is to investigate the connections between time and space, more particularly, geographical changes over time. This is done by focusing on the Study of Land use as a phenomenon and on-going processes in demarcated areas. Distinct areas are given special interest, i.e. how they are used. The study deals with three different kinds of sites in three levels of scale: a market garden, cemeteries and a residential area.The main focus of the study is on the cemeteries.

Since prehistoric time man has used wood to build their environment. The material?s availabilitycombined with its good mechanical properties has often made it the material of choice. Like allmaterials exposed to natures degradative processes the properties of wood decreases over time.Rot, UV radiation and attacks by insects and pests damage wood if not protected. Since we wantwhat we build to consist, optimizing our building materials durability is of great interest.Techniques and methods for increasing the endurance of wood have been developed in severaldifferent places and for a long time.

This thesis has been done at the powder department (GH) at AB Sandvik Coromant in Gimo. With a rheometer measurements has been made on raw materials and powder blends. The focus of this report has been to find correlations between raw material powders and press data, comparisons have also been made between raw materials and powder blends.The rheometer can show information of how a powder act in flow conditions, together with air and with pressure. Analyses has been done comparing the rheometer data with press parameters (for example: rejected orders, weight variations and the compaction pressure) with the goal to find correlations between the powders flow properties and the powders compaction in production.The measurements and analyses have been showing that the powder flow properties depends on the powders composition and that properties like flow rate, aeration and permeability varies between powder blends and batches of the same powder sort. It seems to exist a correlation between the pressure force and the flow rate of a raw material.

TV and radio services have always been distributed over analogue broadcasting networks and been received on a TV -set or a radio receiver. Today this situation is changing due to digitalization and convergence between broadcasting, telecommunications and data communications. Other terminals, such as a PC, can also receive TV and radio services. Digital TV and radio can offer additional services such as e-commerce, electronic program guides and content synchronized to the TV and radio shows. If these services are to be received by several receiving terminals with different properties, the services must be adapted to the terminals.

Uppsala County has ambitious environmental aims for the planned residential area inÖstra Sala backe. In this thesis different energy sources have been evaluated todetermine which system that would be most favorable given currently availableinformation about the project. Planned energy usage has been divided into tap waterheating, space heating and power. Three base case scenarios were made with districtheating, small scale bio fuel and heat pump. Solar power and solar heating were thensimulated and the production from the two could individually be deducted from theenergy need in the base cases, constituting 9 different scenarios.

This thesis has been done at the powder department (GH) at AB Sandvik Coromant in Gimo. With a rheometer measurements has been made on raw materials and powder blends. The focus of this report has been to find correlations between raw material powders and press data, comparisons have also been made between raw materials and powder blends.The rheometer can show information of how a powder act in flow conditions, together with air and with pressure. Analyses has been done comparing the rheometer data with press parameters (for example: rejected orders, weight variations and the compaction pressure) with the goal to find correlations between the powders flow properties and the powders compaction in production.The measurements and analyses have been showing that the powder flow properties depends on the powders composition and that properties like flow rate, aeration and permeability varies between powder blends and batches of the same powder sort. It seems to exist a correlation between the pressure force and the flow rate of a raw material.

This thesis presents the residential development in the city of Uppsala, targeting theliving conditions of young adults and students. In cooperation with Sweco Architect inUppsala. The purpose of this survey is to reveal difficulties and possibilities for theearly development of the construction process for studio apartments. Theinformation has been obtained through both a literature review and interviews. Theliterature review is based on Swedish regulations and previous studies in the field, andthe interviews were conducted with organisations and people in leading positionswithin Uppsala.

The purpose of this investigation was to find out more about students? spontaneous ideas about properties and transformations of matter. Examples of matter chosen are such which students know about from everyday life and focus is mainly on the questions if students know that all matter has weight and that matter is preserved in transformations.The method used is semi structured qualitative interviews with individual students. Different experiments were carried out together with the students who afterwards were interviewed. However, the students show varying answers and no generalizations can be done.