This diploma thesis describes the comparison of two different kinds of structures of snowboard wooden core. One is a combination of ash and poplar (long known and reliable structure currently used by the company Hackboards Ltd.). The other is tested combination when abele is replaced by lighter balsa wood. For both types of core the same types of fibreglass, base and top sheet are used (triaxial fibreglass, sintered base, protective top sheet). The individual mouldings were cut to the required sample on which the tests were made for the determination of bending strength according to ČSN EN 310 and impact bending according to ČSN EN ISO 179-1. Then according to ČSN EN 322 and ČSN EN 323 the moisture and density of used wooden boards were set. The measured results were evaluated and presented in charts and tables in the experimental part of this work.

The aim of this thesis was to analyse the macroscopic structure of the wood of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and determine selected physical and mechanical properties with an emphasis on the comparison of juvenile and mature wood zones. Additionally, the structure and selected properties of the wood from sites varying in the forest types (3K, 3B, 3A) were compared. Five sample trees were sampled in each of the three selected sites. Their rootstock parts were then worked into test specimens with dimensions of 20 x 20 x 30 mm a 20 x 20 x 300 mm. The selected wood properties were the density at moisture content of 0% and 12%, basic density, the total shrinkage in all three basic directions, the total volumetric shrinkage, strength in compression parallel to the grain, bending strength, and the modulus of elasticity in bending. Additionally, a tree-ring analysis was conducted. It was found out that the juvenile wood has wider rings, a lower proportion of earlywood and all the observed properties showed lower values. The properties determined and the structure of the wood from the selected groups of forest types is statistically significantly different in most cases. From the forestry perspective, the resulting material characteristics of wood of Douglas fir are greatly dependent on the site; however, the precise location of the sample within the stem (centre or periphery) has a more pronounced effect on the properties.

This thesis evaluated experimental research on the influence of selected factors (species, thickness, density, number of stress cycles) on the specified material characteristics (modulus of elasticity, modulus of rupture, limit of proportionality, bendability coefficient). The measured values were statistically evaluated and expressed in tables and graphs. Beech (Fagus Sylvatica L.) was selected to represent hardwood and aspen (Populus Tremula L.) softwood. Tree species affects all observed characteristics. The results show that the modulus of elasticity increases with increasing densification of the material, but decreases with the increasing thickness of the material. A similar dependence is observed even with the modulus of rupture and limit of proportionality, which is also dependent on the number of cycles. The bendability coefficient is affected by material thickness. It is expected that based on the evaluation of the results it will be possible to design materials with tailored properties.

Thesis investigates the flexural properties of modified laminated wood. Thesis examined two wood species - beech and aspen. The aim was to describe effect of wood species, material thickness, densification, adhesives and loaded cyclic stress on selection of mechanical properties. Wood species and thickness of material were determined as factors with very significant impact. They affected modulus of elasticity, limit of proportionality and bending strength. All these characteristics achieved higher values while testing beech lamellas. Degree of densification does not appear as a very significant factor. Comparing modulus of elasticity in this thesis and data given in the literature it is possible to say that densified lamellas used in this research reached higher values. This thesis also investigates tensile-shear strength and bendability.

This thesis evaluates properties of board based on mineral fibers. In first part of the thesis is conducted analysis of the literature, where are described materials based on basalt fibers. Here is also explained production of basalt fiber and its practical applications. Sandwich materials and materials with great fire resistance based on wood are also looked into. Following part describes options of aplication of materials with great fire resistance and mechanical a physical properties of materials based on wood. Second part of the thesis lays out methodical approach to individual performed mechanical and physical tests. Characteristic of examined material is included. The last part deals with test results, comparing results with other selected materials, debating results and proposing possible applications of examined basalt board. With use of found data is evaluated suitability of the material for use for construction of sandwich panel.

No description available.

I projektet dimensionerades ett tre våningar högt flerbostadshus i KL-trämoduler med utgångspunkt från dagens byggande av moduler som främst görs i träregelstommar. Vägg- och bjälklagsdimensioner beräknades och ritades upp. Metoder för infästningar och lyft av moduler med träregelstommar undersöktes genom intervjuer och applicerades i den mån som är möjlig för KL-trämoduler. Syftet var att ta fram en konstruktionsutformning för moduler av KL-trä avsedda för bostadsbyggande. Utformningen skall principiellt även kunna användas för andra liknande byggnader. Dimensioneringen visade att KL-träskivorna klarar av lasterna med god marginal. Avgörande för vägg- och bjälklagstjockleken var branddimensioneringen. Infästningar mellan olika byggnadsdelar kan göras på liknande sätt med KL-trä som med träregelstomme. Metoden att använda sig av stålförband i form av vinkelbeslag eller spikplåtar kan användas till de båda stomalternativen. Modullyft kan i viss mån utföras på samma sätt i de båda stommarna. / A three storey tall building was used as a reference object in this project and dimensioned with a starting point from timber frame modular constructions. Wall and floor dimensions are calculated and drawn. Methods for attachment and lifting of modules are examined through interviews and are, when possible, applied for the CLT modules. The purpose of this project was to design CLT modules intended for residential use. The goal of the design was that it can be used in similar buildings. The calculations showed that the fire requirements were the decisive factor when deciding the thickness of the walls and floors. Attachments between different building parts can be designed similarly in both timber frame modules and CLT modules. The method of using angle irons and nail plates is possible for both timber frame and CLT. The lifting of the modules can to some extent be executed similarly for the two frameworks.

This report describes the process and steps in detail that needed to be taken in order to meet the end users’ needs. The purpose of this study is to develop a dynamic module based on user-centered design (UCD) for Pulsen’s (pulsen.se) new website using the con-tent management system (CMS) SiteVision. UCD integrated with agile development methodologies is an effective combination to increase the focus of a development project on the end users’ needs. In this study we show the pervasiveness of the two methods combined in a development project. The module’s functionality is to allow the end user to quickly - and without effort - sort and filter news articles, events and job postings into lists that will be embedded and reusable on their new website. Manual adaptation of custom modules was configured directly through JavaScript code which made them error prone, causing the modules not to function properly. To combat this problem, we used contextual inquiry (CI) along with usability testing as data gathering methods with both Pulsen’s editors and external participants. The usability tests were used to plan and evaluate the functionality of the prototype in order to make it as user-friendly as possible. The study resulted in an interface with user defined variables derived from a JavaScript module.

Följande är en översikt över mitt kandidatarbete som jag arbetade med under våren 2009. Dokumentets första del beskriver projektets mål, uppbyggnad och slutresultat samt min arbetsprocess. I del II reflekterar jag över mitt arbete och vad jag har lärt mig. Till slut finns en ordlista där en del facktermer förklaras, samt några utdrag ur designdokumentet som var en del av mitt projekt. / The following is an overview of the final project of my Bachelor’s Degree, which I worked on during the spring of 2009. The first part of the document describes the goal, creation and final result of the project, as well as the work process. In the second part I reflect on my work and consider what I have learnt. Finally there is a glossary in which some technical terms are explained, as well as a couple of excerpts from the design document that was part of my project. / Detta är en reflektionsdel till en digital medieproduktion.

The goal of this work was to prove the fact, that definable closure of any subclass of cotorsion modules closed under direct sums consists of $\Sigma$-cotorsion modules. The only known proof uses substantially the calculus of derived category, in this work we tried to prove the same, but only by means of a given category of all right $R$-modules and set-theoretic properties of partial orders indexing direct systems of $R$-modules. The main results of this work are proved under additional assumptions on the ring $R$, in particular $\vert R\vert\leq\aleph_{\omega}$ or $\text{dim}(R)<\aleph_{\omega}$. Attempts to give s proof in the same general situation, where the fact is known to hold, was not successful. Powered by TCPDF (www.tcpdf.org)