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This thesis is motivated from the fundamental decision problem in today's manufacturing industry which could be summarized as one simple question: how is it possible to achieve economic growth by taking advantage of the latest technologies while protecting the environment? The machine tool has undergone a remarkable change in recent years and the classical concept of an independent, manually operated machine tool, specially dedicated to a particular machining process no longer belongs to the production environment. The increasing usage of computer control and measuring equipment as well as workpiece and tool handling devices has transformed the machine tool into a sophisticated hybrid production system having a lower demand for human supervision of the process. All these efforts are gathered together in order to achieve a high productivity system able to machine different parts respecting quality requirements at the lowest cost. In addition, increasing attention to the environmental and health impacts by governmental regulations and by growing awareness in society is forcing manufacturers to find environmentally friendly designs and machining strategies. The objective of this research is to propose a multicriteria decision aid methodology (MCDA) for evaluation of the use phase of a machine tool system by jointly considering economical, technical and environmental criteria which allows the decision maker to be in a better position to make sustainable decisions. The evaluation is carried out at two levels by addressing the process level with its local cutting area effects and the main activities of the machine tool system by giving full consideration to reduction/elimination of the cutting fluid and reduction of the overall energy consumption. After carefully reviewing previous research, a consistent hierarchical evaluation criteria structure and an entity relationship diagram characterizing the organizational scheme of a database, which stores the data to be used in the evaluation process, is proposed for each level. As a second step, this thesis proposes a model for estimation of the mechanical energy requirements of the cutting subsystem of a machine tool based on the cutter location data, the cutting parameters and the technical specifications of the spindle and feed axes. The MCDA methodology and the energy consumption model were implemented in a software tool using the VBA (Visual Basic for Applications) language and was validated through various tests consisting in the machining of different milling and drilling features of a prismatic part by employing different cutting parameters and cooling/lubrication alternatives. In addition to the cutting tests, an extensive monitoring of the power share amongst the main subsystems of a modern machining center was carried out and a power data collection framework was proposed. The acquisition, interpretation and storage of the experimental data were supported by a measurement platform developed in the LabVIEW environment.

Storage capacity is a key aspect when validating potential CO2 sequestration sites. Most CO2 storage projects, for obvious reasons, target conventional aquifers (e.g., saline aquifers, depleted hydrocarbon fields) with good reservoir properties and ample subsurface data. However, non-geological factors, such as proximity to the CO2 source, may require storing CO2 in geologically “less-than-ideal” sites. We here present a first-order CO2 storage resource estimate of such an unconventional storage unit, a naturally fractured, compartmentalized and underpressured siliciclastic aquifer located at 670–1,000 m below Longyearbyen, Arctic Norway. Water injection tests confirm the injectivity of the reservoir. Capacity calculations, based on the US DOE guidelines for CO2 storage resource estimation, were implemented in a stochastic volumetric workflow. All available data were used to specify input parameters and their probability distributions. The areal extent of the compartmentalized reservoir is poorly constrained, encouraging a scenario-based approach. Other high-impact parameters influencing storage resource estimates include CO2 saturation, CO2 density and the storage efficiency factor. The hydrodynamic effects of storing CO2 in a compartmentalized aquifer are accounted for by calculating probable storage efficiency factors (0.04–0.79 %) in a fully closed system. The results are ultimately linked to the chosen scenario, with two orders of magnitude difference between scenarios. The fracture network contributes with up to 2 % to the final volumes. The derived workflow validates CO2 storage sites based on initial feasibility assessments, and may be applied to aid decision making at other unconventional CO2 storage sites with significant data uncertainty.

Improper management of pig manure has resulted in environmental problems such as surface water eutrophication, ground water pollution, and greenhouse gas emissions. This study develops and compares 14 alternative manure management scenarios aiming at energy and nutrient extraction. The scenarios based on combinations of thermal pretreatment, anaerobic digestion, anaerobic co-digestion, liquid/solid separation, drying, incineration, and thermal gasification were compared with respect to their energy, nutrient and greenhouse gas balances. Both sole pig manure and pig manure mixed with other types of waste materials were considered. Data for the analyses were obtained from existing waste treatment facilities, experimental plants, laboratory measurements and literature. The assessment reveals that incineration combined with liquid/solid separation and drying of the solids is a promising management option yielding a high potential energy utilization rate and greenhouse gas savings. If maximum electricity production is desired, anaerobic digestion is advantageous as the biogas can be converted to electricity at high efficiency in a gas engine while allowing production of heat for operation of the digestion process. In conclusion, this study shows that the choice of technology has a strong influence on energy, nutrient and greenhouse gas balances. Thus, to get the most reliable results, it is important to consider the most representative (and up-to-date) technology combined with data representing the area or region in question.

The recycling of homogeneous acids imposes great challenges to the feasibility of lignocellulose hydrolysis processes. Although heterogeneous catalysts would offer a perspective to circumvent these challenges, conventional solid acids are instable under the hydrothermal conditions typical of hydrolysis processes. In this regard, acid functionalized carbons appear as auspicious alternatives due to the higher perseverance of carbon frameworks. The strong Brønsted acid sites in sulfonated carbons would be particularly well suited to catalyze the hydrolysis of cellulosic biomass. The utilization of these materials has so far been impeded by the controversy regarding the stability of sulfonic acid groups in carbons. Furthermore, it remains uncertain how the constraints imposed on the reaction system by the insolubility of lignocellulose influence the ability of solid acids to function as hydrolysis catalysts. This thesis shows that hydrothermally stable sulfonated carbons can be prepared by utilizing the structure-stability dependence of sulfonic acid groups in carbonaceous materials. The sulfonation of materials featuring a low degree of graphitization resulted in active solid Brønsted acid catalysts that however deactivated through the leaching of sulfonic acid groups. An in-depth physicochemical characterization of the catalysts paired with a systematic study of the stability of model sulfonic acids, revealed that the leaching-tendency is defined by substituent effects. Activating/deactivating substituents control the hydrothermal stability of aryl sulfonic acids by decreasing/increasing the tendency of the carbon-sulfur bond to undergo solvolysis. The presence of stabilizing and destabilizing substituents was found to be tunable by the temperature dependent decomposition of oxygen containing surface groups. Sulfonation of cellulose carbonized at 350°C resulted in a catalyst with 850 µmol g-1 hydrothermally (180 °C) stable sulfonic acid groups. Additionally, a hitherto unknown mode of deactivation was identified that proceeds by the ion-exchange of cationic impurities with protons of the active sites. This mode of deactivation can be fully overcome by implementing countermeasures to reverse or suppress ion-exchange processes. To tackle the limitations of homogeneous acids, the stable sulfonated carbons were used as catalysts in a semi-batch based lignocellulose hydrolysis process. It was found that the chemical recalcitrance and the insolubility of the substrate imposed strong limitations on the reaction with the catalyst and that soluble product formation occurred predominantly via auto-hydrolysis. The propensity of cellulose to undergo auto-hydrolysis could be enhanced by amorphizing its crystal structure through mechanical pretreatment in ball-mill. A heterogeneously catalyzed hydrolysis was achieved through mechanocatalytic processes facilitated by the concerted ball-milling (CBM) of the sulfonated carbon with the substrate. Sulfonic acid groups were pinpointed as active sites during the mechanocatalytic formation of soluble oligosaccharides. The secondary hydrolysis to monosaccharides in the semi-batch reactor was no longer constrained by the insolubility of the substrate. The combination of CBM pretreatment and hydrolysis in the semi-batch reactor was successfully extrapolated to the conversion of spruce fir wood to achieve yields in C5 and C6 derived products that are competitive with state-of-the-art diluted acid processes.

Hybrid hole-transporting material and selective contact for perovskite solar cells was manufactured by industrially viable materials and methods.

The rate of hip fractures due to falls increases with age. External hip protectors placed over the greater trochanter can prevent hip fractures, but the willingness to wear such protective devices is rather low. Most of the commercially available hip protectors consist either of an energy-absorbing foam pad or of a hard shell that distributes the load to the surrounding tissue. In the present study, a fibre-reinforced shell composed of three curved strips bonded with a ring, was designed and lined with shock absorbing foam. The development of the new shell design was based on quasi-static and impact tests of manufactured shells in combination with finite element simulations. The results of the numerical analysis showed the potential protection effect of the shell and indicated how the design can be further improved. First impact tests on an anatomical hip model showed promising results of the new protector shell in combination with a foam pad.

AbstractGlobal biodiversity is eroding due to anthropogenic causes, such as climate change, habitat loss, and trophic simplification of biological communities. Most studies address only isolated causes within a single group of organisms; however, biological groups of different trophic levels may respond in particular ways to different environmental impacts. Our study used natural microcosms to investigate the predicted individual and interactive effects of warming, changes in top predator diversity, and habitat size on the alpha and beta diversity of macrofauna, microfauna, and bacteria. Alpha diversity (i.e., richness within each bromeliad) generally explained a larger proportion of the gamma diversity (partitioned in alpha and beta diversity). Overall, dissimilarity between communities occurred due to species turnover and not species loss (nestedness). Nevertheless, the three biological groups responded differently to each environmental stressor. Microfauna were the most sensitive group, with alpha and beta diversity being affected by environmental changes (warming and habitat size) and trophic structure (diversity of top predators). Macrofauna alpha and beta diversity was sensitive to changes in predator diversity and habitat size, but not warming. In contrast, the bacterial community was not influenced by the treatments. The community of each biological group was not mutually concordant with the environmental and trophic changes. Our results demonstrate that distinct anthropogenic impacts differentially affect the components of macro and microorganism diversity through direct and indirect effects (i.e., bottom‐up and top‐down effects). Therefore, a multitrophic and multispecies approach is necessary to assess the effects of different anthropogenic impacts on biodiversity.

Six hydrothermal liquefaction experiments on Nannochloropsis salina and Spirulina platensis at subcritical and supercritical water conditions (220–375 °C, 20–255 bar) were carried out to explore the feasibility of extracting lipids from wet algae, preserving nutrients in lipid-extracted algae solid residue, and recycling process water for algae cultivation. GC–MS, elemental analyzer, FT-IR, calorimeter and nutrient analysis were used to analyze bio-crude, lipid-extracted algae and water samples produced in the hydrothermal liquefaction process. The highest bio-crude yield of 46% was obtained on N. salina at 350 °C and 175 bar. For S. platensis algae sample, the optimal hydrothermal liquefaction condition appears to be at 310 °C and 115 bar, while the optimal condition for N. salina is at 350 °C and 175 bar. Preliminary data also indicate that a lipid-extracted algae solid residue sample obtained in the hydrothermal liquefaction process contains a high level of proteins.