We derive the equation linking the Weyl tensor with its Lanczos potential, called the Weyl-Lanczos equation, in 1+3 covariant formalism for perfect fluid Bianchi type I spacetime and find an explicit expression for a Lanczos potential of the Weyl tensor in these spacetimes. To achieve this, we first need to derive the covariant decomposition of the Lanczos potential in this formalism. We also study an example by Novello and Velloso and derive their Lanczos potential in shear-free, irrotational perfect fluid spacetimes from a particular ansatz in 1+3 covariant formalism. The existence of the Lanczos potential is in some ways analogous to the vector potential in electromagnetic theory. Therefore, we also derive the electromagnetic potential equation in 1+3 covariant formalism for a general spacetime.

This master thesis is intended to give an increased understanding of the stress state in an axle, which is assembled in one of Atlas Copco?s mountain drilling rigs. The main problems investigated were how the axle is affected when the bearing is worn, when the pretension is varied, and how to dimension the axle. Answers to these questions were found by using hand calculations, practical testing and with Finite Element analyzes. The dimensioning of the axle is currently based on the bending stress, but the author?s opinion is that the axle should be dimensioned considering the equivalent stress.

Self-compacting concrete has soon been around for a decade. Recently the prefabrication industry has started to use this fairly new concrete type in larger scales, mainly because of its distinctive properties.  There are still certain areas that need to be thoroughly examined, such as bond capacity. There have been very few studies regarding shear capacity due to the fact that the procedure is complicated.This report will highlight a method to examine the shear capacity of different surfaces that have been prewetted as well as non-prewetted surfaces. The surface areas follow BBK 04?s and Eurocode 2?s demand for surface roughness.  A smooth surface will be completed in order to confirm if the different shapes influence the bond strength by shear stress or not.                       The purpose of this essay is to measure the bond strength within the shear capacity as well as examine the impact it has on surface roughness and treatment for shear bond.The method used to identify the shear capacity is called L-shaped Push-Off Test.

This report is about the shear force design of reinforced concrete according to Europe?s common dimension rules, Eurocode. The purpose is to describe the calculation procedure and the background to the formulas and expressions that occurs. Furthermore results from different calculation methods (hand calculations and computer calculations) will be compared to see how they differ.The goal with this is to go through the parts of Eurocode dealing with shear force and that this will lead to a clear review of these. You should also be able to see how results and the calculation procedure differ between different calculation methods.

This report is about the shear force design of reinforced concrete according to Europe?s common dimension rules, Eurocode. The purpose is to describe the calculation procedure and the background to the formulas and expressions that occurs. Furthermore results from different calculation methods (hand calculations and computer calculations) will be compared to see how they differ.The goal with this is to go through the parts of Eurocode dealing with shear force and that this will lead to a clear review of these. You should also be able to see how results and the calculation procedure differ between different calculation methods.

Before the European construction standards were introduced in January 2011, it was mainly themethod in BBK04 that was used for calculating punching capacity in concrete structures, and in lesscommon cases the method in BHB. The method of BBK04 is easy to use and have had the samestructure since the first was published in 1979. The Concrete handbook method (BHB) where usuallyonly used when a higher punching capacity was needed and the cross-sectional height where fixed,calculations using this method entails more work, but will in return usually give a higher capacity. Italso allows the use of shear reinforcement to increase the cross-section capacity. The method ofcalculating punching shear in EC2 differs largely from the methods of BBK04 and BHB.

A today common soil reinforcement method is the installation of lime-cement columns. Lime-cement columns have been used since the 1970?s and have been a useful method for stabilizing soil at great depths. It is mostly used for stabilizing road and railway embankments because the method is economically viable and the columns are easy to install. The total costs for the installation of the lime-cement columns is dependent on the numbers of installed columns, what percentage of lime and cement that has been used and the pattern in which the columns has been installed.

As a leisure time pedagogue I find it hard to have an insight into what children are playing, and how they play when it comes to free play. My experience is that in some free play, conflicts arise, which reveal hierarchies and power structures containing violations, whereas other occasions of free play suddenly come to an end as the pedagogue interferes. In this essay I investigate my responsibility as a leisure time pedagogue during children´s free play, based on two differing play situations. I also investigate the play as a phenomenon by looking into previous research on children?s play and development psychology.

In this empirical study I have investigated how preschool teachers relate to the free play at the preschool. At the same time I have investigated how the free play is adapted into everyday practice in the preschool. Previous research shows that children process what they experienced in the free play. The child retrieves content to play with through things they have experienced, such as family life, preschool and so on. To play, grow and continue, it is important that free play may take place and space in the daily activities at the preschool.

Robotic milking in Automatic Milking systems (AMS) is proposed to reduce manual labour and at the same time increase milk yield by increasing milking frequency. In order to increase milking frequency, it is essential to have well-functioning cow traffic. Investing in an AMS is a great capital investment for the farmer, thus it is of major importance to ensure maximal AMS capacity. This study investigated the effect of the traffic systems Feed First? and Free cow traffic with and without waiting area (WA) on cow performance and AMS capacity.

By applying a segmentation procedure to two different sets of computed tomography scans, two geometrical models of the abdominal aorta, containing one inlet and two outlets have been constructed. One of these depicts a healthy blood vessel while the other displays one afflicted with a Abdominal Aortic Aneurysm. After inputting these geometries into the computational dynamics software FLUENT, six simulations of laminar, stationary flow of a fluid that was assumed to be Newtonian were performed. The mass flow rate across the model outlet boundaries was varied for the different simulations to produce a basis for a parameter analysis study. The segmentation data was also used as input data to a surface description procedure which produced not only the surface itself, but also the first and second directional derivatives in every one of its defining spatial data points.

In this report, the risk of cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.

We have by Statistics Sweden (SCB) been given the task of using different dynamic regression models in order to forecast service price index for sea transport. The aim is to see whether these models provide better forecasts than those previously used. This essay aim to identify, estimate and evaluate the selected prediction models. Through our data material we were given access to 28 sightings of sea transport index during the period of 2004 q1 to 2010 q4. We have chosen to evaluate three different transfer function models, one ARIMA model and one naive forecasting model. The input variables we decided to test in our transfer function models were the price of petroleum products, the port activity in Swedish ports and the lending rate of Swedish Central bank. The results of our study suggest that transfer function models generally provide better models than the ARIMA model and the naive forecast model.

AbstractGroup processes within the free play- in a socialpsychology perspective In our socialpsychology study we have demonstrated how children?s free play is by observing 2-5 years old children in preschool. We have also interviewed two preschool teachers. The major subject in this study is how children?s group processes expresses in their free play.

The purpose of this thesis is to study five pedagogue?s view of the free play and their view of the importance of the free play for children´s learning and development. I have chosen to use a qualitative research method in the form of interviews with five pedagogue´s from a preschool. The main research questions asked were:What have the pedagogues of view on the free play? How important believe the pedagogue that the free play is for children?s learning and development? What has emerged in the study is that educators have a positive view of the free play. They believed that the free play is important for children´s skills.