This thesis presents a detailed study of the simultaneous biaxial stretching of isotactic polypropylene (iPP) films in the partly molten state. Four commercial grades of isotactic PP (PP1--PP4) were investigated. The first three resins differed principally in isotacticity levels, which were 94.8%, 98.6%, and 99.5%, and the fourth resin had molecular weight and isotacticity levels similar to those of PP2, but differed in crystallization behavior. The four iPP resins were extruded and cast under similar conditions. The severity of the cooling was varied for PP4. The cast films were stretched on the laboratory film stretcher, that simulates closely the stretching conditions encountered in the industrial tenter-frame stretching process. The morphology of the cast films and the final stretched films was characterized by differential scanning calorimetry and wide-angle X-ray diffraction. The reflection technique was used for the X-ray measurements. Finally, the mechanical and optical properties of the films were determined, and the results were correlated with the film morphology and orientation. The effects of drawing temperature, stretching ratio, strain rate, initial morphology, and chain tacticity on deformation behavior, stretched film morphology, and end-film properties were studied, and correlations were sought. / Simultaneous equibiaxial stretching was found to be homogeneous for sufficiently high deformation rates ( 3&d2;H > 0.1 s-1). The stiffness and the thermal stability of the crystallites played an important role in deformation behavior. In fact, the biaxial yield stress showed linear dependence on the crystallite size. Upon simultaneous equibiaxial deformation, crystallinity and especially orientation increased, while crystallite size decreased. The isotacticity content was found to influence greatly the thermal stability of the initial morphology. Increasing isotacticity leads to an increase in DSC melting peak temperature of the initial morphology, overall stress of deformation, and in the final crystallinity, orientation, elastic modulus, and tensile strength of the end film. Finally, it was concluded that the crystalline phase, that melts during preheating prior to stretching forms a "structured melt" phase. The amount of structured melt is related to the tensile strength at break of the end film. Finally, it was showed that an optimal gloss is obtained, if the cast film is stretched about 15°C below its melting point.

This thesis concerns the robustness of structures considering various uncertainties. The overall objective is to evaluate and develop simulation based design methods in order to find solutions that are optimal both in the sense of handling typical load cases and minimising the variability of the response, i.e. robust optimal designs. Conventionally optimised structures may show a tendency of being sensitive to small perturbations in the design or loading conditions. These variations are of course inevitable. To create robust designs, it is necessary to account for all conceivable variations (or at least the influencing ones) in the design process. The thesis is divided into two parts. The first part serves as a theoretical background for this work. It includes introductions to the concept of robust design, basic statistics, optimisation theory and metamodelling. The second part consists of five appended papers on the topic. The first and third papers focuse on the evaluation of robustness, given some dispersions in the input data. Established existing methods are applied, and for paper three, comparisons with experimentally evaluated dispersions on a larger system are made. The second and fourth paper introduce two new approaches to perform robust optimisation, i.e. optimisations where the mean performance and the robustness in the objectives are simultaneously optimised. These methods are demonstrated both on an analytical example and on a Finite Element model design example. The fifth paper studies the variations in mechanical properties between several different batches of the same steel grade. A material model is fitted to each batch of material, whereby dispersions seen in test specimens are transferred to material model parameter variations. The correlations between both test and material model parameters are studied.

This thesis concerns structural optimization and robustness evaluations, and new methods are presented that considerably reduce the computational cost of these evaluations. Optimization is an effective tool in the design process and the interest from industry of its usage is quickly increasing. However, the usage would probably have grown faster if the required number of computationally costly finite element analyses could be reduced. Especially in the case of product family optimization, the problem size can easily get too large to be solved within a reasonable time. This is sometimes also true for robustness evaluations. To enable the usage of optimization and robustness evaluations also for large scale industrial problems, two new methods are here presented, which require a considerably smaller number of finite element analyses. The first method concerns structural optimization of product families subjected to multiple crash load cases. Here, the number of required finite element analyses are considerably reduced by only considering the critical constraint in each iteration step. The second method is an approach to approximate the variable sensibility based on the distribution of internal energy in a structure. The method can be used to evaluate the relative robustness of different design proposals or for structural optimization. Since the method is independent of the number of parameters and design variables the computational cost of such evaluations is drastically reduced for computationally large problems.

Energy conservation, energy efficiency measures, and energy carrier conversion within the industry are extremely important issues in order to deal with energy resource depletion and the threats from global warming. In Swedish industry there is potential for reductions of carbon dioxide emissions and resource use through utilization of excess heat and conversion of compression cooling to other cooling technologies using less electricity. Co-operation between industries and utilities can be obtained concerning both heating and cooling, but the choice of technologies and the profitability of co-operation are influenced by a number of factors such as the type of industry, policy instruments, the size and design of the district heating and cooling systems, and energy market prices. In this thesis, energy co-operation has been studied on two levels: a techno-economic level and a socio-technical level. On the techno-economic level the possibilities for co-operation in two industrial cases have been studied, Scandinavian kraft pulp mills and manufacturing industry in the municipality of Södertälje: The pulp and paper industry is one of the major energy users in Sweden, and 2.2 TWh of heat was delivered from pulp mills in 2007, mainly to district heating systems. At kraft pulp mills the excess heat can be used either internally or externally. Internally, excess heat can be used in the production process and/or to replace steam and thereby increase the production of electricity, depending on the quality of the excess heat. Externally, excess heat can be used as district heating. The trade-off between internal and external use of excess heat depends on numerous factors. The economic profitability of possible investments is influenced not only by investment costs and fuel costs; several policy instruments, including the electricity certificate system and the carbon dioxide trading scheme, also influence the choice of technology as well as the willingness to co-operate. In the municipality of Södertälje two large industries use large amounts of electricity, district heating and cooling. The cooling demand in Södertälje is currently covered by free cooling from lake water and compression chillers; but in order to reduce the use of electricity, conversion to heat-driven cooling or increased lake water cooling can be considered. The large CHP plant in Södertälje is today not used to its full potential, but investment in heat-driven cooling and/or a cold condenser unit integrated with the CHP plant could increase the plant’s operation hours. New investments in district cooling could increase the level of co-operation between the two industries and the local utility, but depending on policy instruments, energy market prices and the possible exchange of heat between Södertälje and Stockholm, the profitability of such investments will vary. On the socio-technical level, co-operation between utilities and industries has been studied through interviews and surveys to further analyze factors concerning co-operation beyond the techno-economic level. Results from the studies show that communication between the parties, the willingness to take risks, and trust between the co-operating parties are key factors that are as vitally important for a co-operation to take place as technical and economic factors. / Energibesparingar, energieffektivitet och konvertering av energibärare i industrin är oerhört viktiga frågor att hantera med tanke på det hot vi står inför med uttömning av resurser och global uppvärmning. I svensk industri finns det potential för reducering av koldioxidemissioner och resursanvändning genom utnyttjande av industriell överskottsvärme och konvertering av kompressionskyla till andra kyltekniker som använder mindre el. Samarbete mellan industrier och energibolag kan uppnås både för värme och kyla, men valet av teknik och lönsamheten i samarbete påverkas av ett flertal faktorer som typen av industri, styrmedel, storleken och produktionsmixen i fjärrvärme- och fjärrkylanäten samt energimarknadspriser. I den här avhandlingen har energisamarbeten studerats på två olika nivåer: en tekno-ekonomisk nivå och en socio-teknisk nivå. På den tekno-ekonomiska nivån har möjligheter till samarbete undersökts i två industriella fall, skandinaviska kemiska massabruk och tillverkningsindustri i Södertälje. Massa- och pappersindustrin är en av de största energianvändarna i Sverige och 2,2 TWh värme levererades 2007 från olika bruk till fjärrvärmenäten. I ett kemiskt massabruk kan överskottsvärme användas antingen internt eller externt. Intern kan värmen användas i produktionsprocesserna och/eller för att ersätta ånga och därmed öka elproduktionen, beroende på överskottsvärmens kvalitet. Externt kan värmen användas till fjärrvärme. Avvägningen mellan intern och extern användning beror på flera faktorer. Den ekonomiska lönsamheten för möjliga investeringar påverkas inte bara av investeringskostnader och bränslekostnader, ett flertal styrmedel, inklusive elcertifikatsystemet och handeln med utsläppsrätter, påverkar valet av teknik och viljan att samarbeta. I Södertälje finns två stora industrier som använder stora mängder el, fjärrvärme och kyla. Kylbehovet i Södertälje täcks för närvarande av frikyla från sjövatten och kompressionskylmaskiner, men för att minska elanvändningen kan konvertering till värmedriven kyla eller en ökning av mängden frikyla vara aktuellt. Den stora kraftvärmeanläggning som finns i Södertälje utnyttjas idag inte till sin fulla potential, men investering in värmedriven kyla kan öka drifttiden i anläggningen. Nya investeringar i fjärrkyla kan ge ett ökat samarbete mellan industrierna och energibolaget i Södertälje, men beroende på styrmedel, energimarknadspriser och det fjärrvärmeutbytet mellan Södertälje och Stockholm, kommer lönsamheten i dessa investeringar att variera. På den socio-tekniska nivån har samarbeten mellan industrier och energibolag undersökts genom intervjuer och enkäter för att ytterligare analysera de faktorer som påverkar samarbeten utöver de tekno-ekonomiska möjligheterna. Resultaten från studierna visar att kommunikation mellan parterna, vilja att ta risker och förtroende mellan parterna är faktorer som är lika viktiga för att uppnå ett samarbete som tekniska möjligheter och ekonomisk lönsamhet.

The wireless market has experienced a remarkable development and growth since the introduction of the first modern mobile phone systems, with a steady increase in the number of subscribers, new application areas, and higher data rates. As mobile phones and wireless connectivity have become consumer mass markets, the prime goal of the IC manufacturers is to provide low-cost solutions. The power amplifier (PA) is a key building block in all RF transmitters. To lower the costs and allow full integration of a complete radio System-on-Chip (SoC), it is desirable to integrate the entire transceiver and the PA in a single CMOS chip. While digital circuits benefit from the technology scaling, it is becoming harder to meet the stringent requirements on linearity, output power, bandwidth, and efficiency at lower supply voltages in traditional PA architectures. This has recently triggered extensive studies to investigate the impact of different efficiency enhancement and linearization techniques, like polar modulation and outphasing, in nanometer CMOS technologies. This thesis addresses the potential of integrating linear and power-efficient PAs in nanometer CMOS technologies at GHz frequencies. In total eight amplifiers have been designed - two linear Class-A PAs, two switched Class-E PAs, and four Class-D PAs linearized in outphasing configurations. Based on the outphasing PAs, amplifier models and predistorters have been developed and evaluated for uplink (terminal) and downlink (base station) signals. The two linear Class-A PAs with LC-based and transformer-based input and interstage matching networks were designed in a 65nm CMOS technology for 2.4GHz 802.11n WLAN. For a 72.2Mbit/s 64-QAM 802.11n OFDM signal with PAPR of 9.1dB, both PAs fulfilled the toughest EVM requirement in the standard at average output power levels of +9.4dBm and +11.6dBm, respectively. The two PAs were among the first PAs implemented in a 65nm CMOS technology. The two Class-E PAs, intended for DECT and Bluetooth, were designed in 130nm CMOS and operated at low ‘digital’ supply voltages. The PAs delivered +26.4 and +22.7dBm at 1.5V and 1.0V supply voltages with PAE of 30% and 36%, respectively. The Bluetooth PA was based on thin oxide devices and the performance degradation over time for a high level of oxide stress was evaluated. The four Class-D outphasing PAs were designed in 65nm, 90nm, and 130nm CMOS technologies. The first outphasing design was based on a Class-D stage utilizing a cascode configuration, driven by an AC-coupled low-voltage driver, to allow a 5.5V supply voltage in a 65nm CMOS technology without excessive device voltage stress. Two on-chip transformers combined the outputs of four Class-D stages. At 1.95GHz the PA delivered +29.7dBm with a PAE of 26.6%. The 3dB bandwidth was  1.6GHz, representing state-of-the-art bandwidth for CMOS Class-D RF PAs. After one week of continuous operation, no performance degradation was noticed. The second design was based on the same Class-D stage, but combined eight amplifier stages by four on-chip transformers in 130nm CMOS to achieve a state-of-the-art output power of +32dBm for CMOS Class-D RF PAs. Both designs met the ACLR and modulation requirements without predistortion when amplifying uplink WCDMA and 20MHz LTE signals. The third outphasing design was based on two low-power Class-D stages in 90nm CMOS featuring a harmonic suppression technique, cancelling the third harmonic in the output spectrum which also improves drain efficiency. The proposed Class-D stage creates a voltage level of VDD/2 from a single supply voltage to shape the drain voltage, uses only digital circuits and eliminates the short-circuit current present in inverter-based Class-D stages. A single Class-D stage delivered +5.1dBm at 1.2V supply voltage with a drain efficiency and PAE of 73% and 59%, respectively. Two Class-D stages were connected to a PCB transformer to create an outphasing amplifier, which was linear enough to amplify EDGE and WCDMA signals without the need for predistortion. The fourth outphasing design was based on two Class-D stages  connected to an on-chip transformer with peak power of +10dBm. It was used in the development of a behavioral model structure and model-based phase-only predistortion method suitable for outphasing amplifiers to compensate for both amplitude and phase mismatches. In measurements for EDGE and WCDMA signals, the predistorter improved the margin to the limits of the spectral mask and the ACLR by more than 12dB. Based on a similar approach, an amplifier model and predistortion method were developed and evaluated for the +32dBm Class-D PA design using a downlink WCDMA signal, where the ACLR was improved by 13.5dB. A least-squares phase predistortion method was developed and evaluated for the +30dBm Class-D PA design using WCDMA and LTE uplink signals, where the ACLR was improved by approximately 10dB.

The research conducted for this thesis was focused on supporting mobile users, developing "bring your own support" solutions in order to ensure that minimum levels of computational support are always available to the user. The first line of research developed ways to minimize the negative social consequences arising from technology use. The second line of research concentrated on garment integrated devices, their use construction, and management of smart garments. The third line of research concentrated on device deployment which are another aspect of the "bring your own support" approach to supporting the mobile user. / Thesis (PhD)--University of South Australia, 2007.

Thesis (MEducation)--University of South Australia, 2002.

Thesis (MEducation)--University of South Australia, 2002.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--Indiana University, School of Education, 2007. / Source: Dissertation Abstracts International, Volume: 68-09, Section: A, page: 3816. Adviser: Charles M. Reigeluth. Title from dissertation home page (viewed May 8, 2008).