During this master thesis project, various polymer materials have been studied in relation to additive manufacturing. Additive manufacturing is a 3D printing process that has facilitated the productivity of the company, Volvo Cars. The printing process is based on a design conceived from CAD software. The final design is sent in digital form to the printer from which the prototype is built, layer by layer, until the finished product is finished. This thesis project analyzed which polymers would work the best in Volvo’s car industry as to durability and sustainability. A limited number of polymers were chosen for investigation, some also with various additives to change the microstructure and properties. The tensile strength of the polymers was tested, yielding their Young´s modulus. Tests were also performed to measure the wear resistance of the samples. The design of the samples was decided to be a circular disk. The reason behind was that the samples should not be too thin or have a too complicated shape, the inner structure being solid. The primary data were the possible changes in thickness. These samples were afterwards examined under a stereo microscope in order to obtain a 2D image of how the surface had changed. From all the polymers investigated, the tensile tests showed that PA12 CF(polyamide 12 carbon fiber) had the best strength as it contains carbon fibres which stabilizes the material. However, as for wear resistance the polymers PC (polycarbonate) and TPU( thermoplastic polyurethane) could handle more punches before they fractured. PC has the advantages of being very strong, due to very strong bonds between the atoms within the polymers chains, and at the same time constituting a very flexible material. TPU is also a very strong and flexible material, and it has the extra advantage of being suitable for large components. Considering these aspects, these three materials are selected as efficient and suitable for making mechanical components. As a result from this very investigation, they are recommended for making prototypes or components that have good strength and wear resistance.

There is an important potential for a development of a building system, if the present AACblock plants are completed with high performance concrete and pre-stressing technique. This can be done as a continuation of a present AAC production or in a site factory. Hybrid cooperation between AAC and concrete is not a new technology. Traditionally, AAC is covered with rendering. The wetted material is first sprayed with cement slurry after which comes lime/cement-based rendering which strengthens the wall and supplies a mechanical protection. AAC blocks can be used as infill members in concrete deck plates and concrete framed walls (Hellers, 1993), in which the shrinkage of the surrounding concrete locks completely the cured blocks into a stable composite. A good cooperation between AAC and concrete is a requirement for the pre-stressed hybrid. This combination has been investigated with reference to bond and moisture content. The interface must have sufficient bond to supply shear strength to the structural member. Also, the concrete should be suitable for pre-stressing which requires a minimum strength class K40. Here, K60 is applied in order to reduce creep and avoid creep failure of the AAC. A production layout for the purpose is suggested. This research consists of three parts: 1- Hybrid concrete elements The principal formulation of hybrids, built on cooperation between two concrete materials, a weak AAC and a strong HPC poured on top, shows that this combination unites the most favourable qualities of the two concretes into a structural element with rational building technology. Load-bearing capacity is good, and the fire protection is excellent. Through pre-stressing of the structural concrete, a crack-free behaviour is guaranteed up to the service limit, and deflection from dead weight (incl. floor covering and possibly half the service load) be eliminated. The most important structural elements needed in a building system could be taken as hybrids. In drawings, different members like floor- roof- and wall members, window and door lintels are shown. 2- Production system for hybrids AAC blocks form a bed containing the pre-stressing steel in slits and on which high performance concrete is poured. Pre-stressing brings the two concretes together. This is especially important for the shear capacity of a building member, by which extra dowels can be omitted. The pre-stressing force is anchored by plates directly against the cured AAC blocks. A special pre-stressing bed is not required. The production is arranged in such a way that necessary equipment (trays, form strips, wedges, locks) are circulated within twenty-four hours. The necessary manpower for this facility is analysed. Normally 8 men are needed per shift. A detailed conceptual production layout for a hybrid production plant is included for discussion. See figure 6.2 (suggested production layout). 3- Application in building The hybrid members are united at joints and through seams. Continuity over connections is achieved by filling seams with mortar grout. Reinforcement may be included to achieve ductility. By a similar method, it is possible to make connections between horizontal and vertical building members. Common connection details are shown in the report. This building method replaces the equivalent method with concrete or AAC members, and it is in fact a coordination between these two. The maximum span of floor members is up to 9 m. It makes the system suitable for modern residential house production, but also suitable for office buildings, industrial halls and other applications. See attached drawings, part 2 and part 3. / QC 20101109

QC 20101118

In the design of structures to resist the effects of air blast loading or other severe dynamic loads it is vital to have large energy absorbing capabilities, and structural elements with large plastic deformation capacities are therefore desirable. Structures need to be designed for ductile response in order to prevent partial or total collapse due to locally failed elements. The research in this thesis considers experimental and theoretical studies on concrete beams of varying concrete strength. The nominal concrete compressive strength varied between 30 MPa and 200 MPa. A total of 89 beams were tested of which 49 beams were reinforced with varying amounts of tensile reinforcement. These beams were also reinforced with stirrups and steel fibres were added to a few beams. The remaining 40 beams were only reinforced with steel fibres with a fibre content of 1.0 percent by volume. Two different fibre lengths having constant length-to-diameter ratio were employed. The tests consisted of both static and air blast tests on simply supported beams. The blast tests were performed within a shock tube with a detonating explosive charge. All experimental research focused on deflection events, failure modes and loads transferred to the supports. The dynamic analyses involve single-degree-of-freedom (SDOF) modelling of the beam response and the use of iso-damage curves. Also, the dynamic support reactions were calculated and compared with test results. For beams with tensile reinforcement, the failure mode of some beam types was observed to change from a flexural failure in the static tests to a flexural shear failure in the dynamic tests. Beams with a high ratio of reinforcement and not containing steel fibres failed in shear, whereas beams with a lower ratio of reinforcement failed in flexure. The introduction of steel fibres prevented shear cracks to develop, thus increasing the shear strength of the beams. The presence of steel fibres also increased the ductility and the residual load capacity of the beams. Beams subjected to air blast loading obtained an increased load capacity when compared to the corresponding beams subjected to static loading. The SDOF analyses showed good agreement with the experimental results regardless of concrete strength and reinforcement amount. The results of using iso-damage curves indicate conservative results with larger load capacities of the beams than expected. The theoretical evaluations of the dynamic reactions were in agreement with the measured average reactions, both in amplitudes and in general shape. The experimental results with steel fibre reinforced concrete beams indicate that the dynamic strength was higher than the corresponding static strength and that the toughness was reduced when increasing the compressive strength. Beams of normal strength concrete failed by fibre pull-out while a few beams of high strength concrete partly failed by fibre ruptures. It may be favourable to use shorter fibres with smaller aspect ratios in structural elements of high strength concrete and subjected to large dynamic loads. Further research should involve studies on the size effect, on different boundary conditions, on different types of structural elements and on the combination of blast and fragment loads. The theoretical work should involve analyses both with the use of SDOF modelling and finite element analysis. / QC 20101112

Målet med detta examensarbete är att ta fram de möjliga spännvidderna vid tillämpningen av KL-trä (Korslimmat trä) som ett pelardäck. När en tvådimensionell platta läggs över pelare uppstår tryckkrafter och deformationer. Vid användningen av KL-trä som pelardäck uppstår det tryckkrafter riktade vinkelrätt mot fiberriktningen. Detta utgör ett problem eftersom denna typ av belastning är en av träets svagare hållfastheter. När pelarstommar tidigare byggts har betong varit det självklara valet. Betong erbjuder till skillnad från trä en hög tryckhållfasthet och medför även andra fördelar. En nackdel med betong är att den har ett högt klimatavtryck. Därför undersöks möjligheterna för ökad användning av klimatsmartare alternativ som trä. Genomförandet av denna uppgift sker med hjälp av handberäkningar och programvaran FEM-Design som bland annat beräknar deformationer. Resultatet visar att de maximala spännvidderna som kan uppnås med KL-träsortimentet som erbjuds idag uppgår till 5 x 7 meter. Dessa spännvidder görs möjliga tack vare en produkt s.k. Spider som hanterar de stora tryckkrafterna. / This thesis aims to determine the possible lengths between columns when a CLT (Cross Laminated Timber) is applied as a flat slab. When a two dimensional plate is supported by columns, compression and deformation occur. As the CLT is supported the compression forces are directed perpendicular to the grain. This presents a certain problem since wood’s ability to absorb this type of load is one of its weaker properties. As flat slabs previously have been built, concrete has been the obvious choice. Concrete provides high strength when exposed to compressive loads as well as bringing other advantages. One disadvantage with concrete is its great impact on the environment. Therefore, studies are trying to find more climate-smart solutions, such as wood. To establish results for this task a series of test in the software FEM-Design was used to determine the deformations. To determine the compression forces additional calculations was made by hand. The results showed that with the current assortment offered by todays CLT-manufacturers, the CLT can be supported by columns with a span of 5 x 7 m. This was made possible due to a product that was found called Spider which transforms compression forces to tensile.

In order to perform research using novel systems it is first important to distinguish if the collecteddata reflects the manipulations performed by the researcher or the fact that the system might beunfamiliar to the subject. Especially when using highly complex systems such as trainingsimulators, researchers should aim to begin their studies by ensuring that the system is fullylearned. The current study used a virtual reality simulation of a futuristic reconnaissance missionscenario to investigate how performance, mental workload and psychophysiologicalmeasurements changed during repeated training and how data would reflect an additional stimulusappearance after the system had been learned. The results confirmed pre-existing theories oflearning and showed that response to additional tasks after the system had been learned wouldfluctuate but not reach the same levels that were visible at the beginning of the training. Thissmaller increase in response could be assumed to accurately reflect the manipulation of thescenario rather than the novelty of the system.

The adoption and diffusion of electronic technologies into the higher education are complex processes. This study was formulated to see which factors might influence faculty members' motivation and inclination to adopt new electronic technologies in their delivery of instruction. The following research questions were addressed in this study: a) What social variables are involved in the decision to adopt electronic technologies used in the delivery of instruction? b) What organizational variables are involved in the decision to adopt electronic technologies used in the delivery of instruction? c) What personal motivational variables are involved in the decision to adopt electronic technologies used in the delivery of instruction? d) What is the relationship between the social factor with size of the university, size of the department, rank, tenure status, level of experience, and adopter behavior categories? e) What is the relationship between the organizational factor by size of the university, size of the department, rank, tenure status, level of experience, and adopter behavior categories? f) What is the relationship between the personal motivational factor by size of the university, size of the department, rank, tenure status, level of experience, and adopter behavior categories? g) What is the relationship between the social factor and the types and frequency of technology used? h) What is the relationship between the organizational factor and the types and frequency of technology used? i) What is the relationship between the personal motivational factor and the types and frequency of technology used? j) What is the relationship between self-selected adopter categories and the types and frequency of technology used? k) What comparison can be made between a priori adopter categories and self-selected adopter categories? The sample consisted of accounting faculty who taught an introductory accounting class at 12 of the 16 public 4-year institutions of higher education that are in North Carolina, who have accredited Schools or Colleges of Business. The results of this study reinforce the need for administrators and faculty to be made aware of the many social, organizational, and personal motivational factors that can assist and affect a faculty member's decision to use and adopt electronic technologies. Social variables that include friends, mentors, peer support, and students were found to significant in their influence related to a faculty members' decision to adopt electronic technologies in the classroom. Organizational variables of physical resource support and mandate from the university were reported by faculty to also be statistically significant in their influence. All three personal motivational variables emerged as important in the decision to adopt instructional technologies. With the recognition of these social, organizational, and personal motivational factors environments could be developed that enhance and establish the appropriate settings and goals for incorporating instructional technologies into higher educational settings. / Ed. D.

This study identifies substantive issues and suggests guidelines for using assistive technology (AT) in academic libraries. The Delphi Technique was used with a panel of librarians, disability service providers, and AT experts to determine these issues and guidelines for AT services in academic libraries. There were 55 substantive issues identified by a panel of experts for providing appropriate AT in an academic library setting. Some of these issues included training opportunities, providing adequate funding for the purchase and maintenance of AT, funding for staff in-service training and training for individuals with disabilities, evaluation of AT services, and including individuals with disabilities in AT decision making. Accessibility and marketing issues also emerged. A professional panel consisting of 12 library, AT, and disability services experts developed guidelines for these issues. The panel rated the desirability of the guidelines using a Likert-type scale (1= important, 2=relevant problem, 3= insignificantly relevant problem, and 4=no relevance). All issues and guidelines receiving two-thirds of the responding panelists' ratings were included in the important and relevant categories. It was predicted that if librarians plan AT services and training, and market AT services using a collaborative approach that would include librarians, faculty, staff and students with disabilities that AT services could be better provided for students with print disabilities. The panel suggested that funding issues may be resolved in some cases by working cooperatively with other departments and community agencies. / Ph. D.

Our future is moving towards a stricter energy requirement and this means that more and more focus is placed on energy-efficient heating systems in new and existing homes. The most common heating system in Sweden is district heating, and second place comes heatpumps. District heating is, for the most part, an environmentally friendly heating system. The combustion for district heating is usually from biofuel and waste, these two being the main core of district heating production. But in extreme cold during the winter, more heat is needed, which then has its basis in fossil fuels such as oil. The purpose of this thesis is to determine specific energy use for a newly designed villa (116) and then compare it with a nine year old villa (Trubaduren) .

It was theorised that a drag-and-drop based graphic user interface could be implemented to facilitate creation of XML schema without the need of the user to write any XML code. The interface was designed with consideration to the user experience and the needs of the intended user. The report documents the design process and argues for the decisions made.  Ultimately, an application was developed that allows for the creation of XML schema without the user needing to write any XML code themselves and the response from contributors knowledgeable in the field has been positive. User tests of whether the interface itself was sufficiently intuitive to use were inconclusive due to errors in the testing process and would require further investigation before any conclusions could be made