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This thesis delivers an in-depth investigation into electrochemical carbon dioxide reduction (CO2R), a process with the potential to convert CO2 gas into value-added chemicals and fuels. However, the efficiency and operational durability of current CO2 reduction processes are limited by catalytic performance. To address this, the thesis focuses on gaining a deep understanding of the transformations that CO2R electrocatalysts undergo under realistic conditions, such as morphological, phase structure, and compositional changes. These insights inform the design of next-generation materials by identifying performance descriptors and degradation patterns. A key aspect of this thesis is the development and application of in-situ liquid phase transmission electron microscopy (LP-TEM), an advanced platform that directly correlates nanoscale changes in catalyst materials under the influence of electrode potentials in CO2R reactive environments. Despite its potential, the use of in-situ LP-TEM presents a range of challenges, which this thesis addresses alongside exploring potential advancements for enhancing its accuracy and applicability. With the evolution of nanofabricated liquid cells, dynamic nanoparticle tracking, and high-resolution imaging in a liquid medium, this technology can more accurately mimic realistic exposure conditions. Cumulatively, this thesis systematically navigates the technical hurdles, advancements, and future prospects of in-situ LP-TEM in the context of electrochemical CO2R. The findings not only advance our understanding of the in-situ LP-TEM technical process but also guide new researchers in the field of in-situ TEM of electrocatalyst materials, aiding in the optimization of catalyst design, and paving the way for more sustainable and economically competitive CO2R technologies. The application of in-situ LP-TEM extends to the examination of two specific catalysts: Palladium (Pd) and a bi-metallic alloy of Copper (Cu) and Silver (Ag). By employing in-situ LP-TEM and selected area diffraction (SAD) measurements, we trace the morphological and phase structure transformations of the Pd catalyst under CO2R conditions. Interestingly, our findings indicate that alterations in reaction energetics, rather than morphological or phase structure changes, chiefly govern catalyst selectivity. This provides invaluable insights for designing more efficient catalysts. Further, we observe the morphological transformation of a metallic copper catalyst structure into a Cu-Ag bimetallic alloy during a galvanic replacement method. We then investigate the stability of both catalyst structures under operational CO2R conditions. Our results reveal that the metallic Cu structure undergoes significant morphological deformation during CO2R, leading to migration, detachment, and recrystallization of the catalyst surface. Contrarily, the Cu-Ag bimetallic alloy demonstrates notable thermodynamic stability under a similar applied potential. / Thesis / Candidate in Philosophy / This PhD thesis focuses on the development and implementation of cutting-edge technologies to address the climate change implications of CO2 emissions - a potent greenhouse gas. CO2 molecules could be electrochemically converted into various chemical feedstock and fuels. This process involves the development of efficient catalyst designs that can reduce CO2 gas at high conversion rates. Acquiring mechanistic insights on the behavior of the developed catalysts under reaction conditions would significantly assist on producing performance descriptors for catalyst design in CO2 conversion approach. Among a range of different advanced techniques, in-situ liquid phase transmission electron microscopy (LP-TEM) technology is selected for this study. This technique is capable of correlating dynamic nanoscale compositional and morphological changes with the electrochemical response of the catalysts. The primary focus of the thesis is on developing and implementing in-situ LP-TEM techniques to achieve electrochemical CO2 conditions while tracking particle morphology and phase structures as functions of electrochemical potential and time. Furthermore, the thesis investigates the performance of different catalyst designs under CO2 reduction (CO2R) operational conditions, which includes palladium (Pd) nanoparticles and copper–silver (Cu–Ag) bimetallic alloys. On a fundamental level, these studies provide a detailed understanding of the phase transformation and structural changes of these catalysts during CO2R that contributes valuable knowledge to the field and can be used to design next-generation CO2R catalysts.

Numerical simulations utilizing the code SURFER++ with the incorporation of an insoluble surfactant in the VOF scheme were conducted to characterize the effects of surfactant on a drop in shear flow. The drop is suspended in a matrix liquid. A parameter called reduction, which specifically relates to a percentage decrease in effective surface tension, is used to measure the surfactant amount on the interface. In a model system where reduction = 0.1, viscosity ratio = 1 and density ratio = 1, it was found that stable drops tend to be more elongated and less inclined to the primary flow direction than drops unexposed to surfactant. This can be explained by the location of surfactant at the interface as the drop evolves. Breaking drops also show a flattened angle, but exhibit shorter necks and faster time to break than similar drops without surfactant. As reduction increases, various physical characteristics of the drops change across Reynolds number. / Ph. D.

The bachelor's thesis analysed the environmental impact of the Swedish VAT-reduction on minor repairs of 2017 through integrated quantitative and qualitative analysis.:1. Introduction 2. Theoretical Foundations 2.1. Relevant Concepts 2.2. Economic Theory 2.2.1. Market Mechanism, Market Failure and Externalities 2.2.2. Environmental Policies against Market Failure through Externalities 2.2.3. Rebound Effect 2.3. Swedish VAT Reduction – Economic Point of View 2.4. International Context 3. Quantitative Data Analysis 3.1. Methodology 3.1.1. Difference-in-Differences Approach and Control Group Selection 3.1.2. Statistical Significance of Correlations 3.2. Results 3.2.1. Resource Accounts 3.2.2. Waste 3.2.3. CO2e-Emissions 3.2.4. Circular Economy 3.3. Discussion 3.3.1. Resource Accounts 3.3.2. Waste 3.3.3. CO2e-Emissions 3.3.4. Circular Economy 3.3.5. Summary 4. Qualitative Comparative Literature Analysis 4.1. Methodology 4.2. Results 4.2.1. Observed Effect of VAT-Reduction by Stakeholders 4.2.2. Reasons for low Effect and Barriers 4.2.3. Actions Proposed 4.3. Discussion 5. Conclusion

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The liquid phase autoxidation of 1,3-pentadiene to 2,4-pentadienoic acid utilizing gaseous oxygen at atmospheric pressure was investigated as a possible route for direct utilization of piperylene obtained during the cracking of naptha to ethylene. Catalyst system consisting of cobalt, manganese, and iron salts promoted by sodium, potassium and hydrogen bromides, were used under a variety of condition of catalyst concentration, temperature, oxygen flow and piperylene purity. Under all conditions studied, a large number of oxidation products were formed. Maximum yields of 2,4-pentadienoic acid were obtained using a cobalt acetate bromide catalyst at 85°C.

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One of the problems in organizations, especially in hospitals, is that injury rates are increasing because most safety programs lack the essential safety measures for accident reduction in the workplace. The study examined the safety measures that played a role in accident and injury reduction in the workplace. Specifically, the old and new safety programs of an anonymous company was investigated to identify the safety measures that distinguished both programs, their impact on injury rates, and whether the variables of safety program and the variables of safety performance are independent. Data were described by a narrative method, displayed by descriptive statistics, and analyzed by chi square test of independence. The results showed that: (1) The new safety program had twenty-one additional safety measures more than the old safety program; (2) The old safety program increased the recordable injuries by an average of 85%, increased lost workday cases by an average of 14%, and increased incidence rates by an average of 31%; (3) The new safety program decreased the recordable injuries by 48%, decreased lost workday cases by 3%, decreased incidence rates by 51%, and decreased lost workday rates by 12%; and (4) chi square test of independence showed that the safety performance for the recordable injuries and lost workday cases were different across the old and new safety programs. X² (1, N = 1259) = 29.76, p < 0.001. The researcher concluded that: (1) The new management at the company was committed to safety performance improvements; (2) The new safety program performed better than the old safety program; and (3) safety performance variables were dependent of the safety program variables. The researcher recommended that the new management finalize pending policies and also, to perform facility safety inspections semi-annually rather than annually in selected areas so that hazards can be identified more quickly. Lastly, this study and the results thereof, provided useful information to safety professionals and organizations that plan to develop and implement a successful safety program that will reduce accidents and injuries in the workplace.

A model reduction technique that is optimal in the H_∞-norm has long been pursued due to its theoretical and practical importance. We consider the optimal H_∞ model reduction problem broadly from an interpolation-based approach, and give a method for finding the approximation to a state-space symmetric dynamical system which is optimal over a family of interpolants to the full order system. This family of interpolants has a simple parameterization that simplifies a direct search for the optimal interpolant. Several numerical examples show that the interpolation points satisfying the Meier-Luenberger conditions for H₂-optimal approximations are a good starting point for minimizing the H_∞-norm of the approximation error. Interpolation points satisfying the Meier-Luenberger conditions can be computed iteratively using the IRKA algorithm [12]. We consider the special case of state-space symmetric systems and show that simple sufficient conditions can be derived for minimizing the approximation error when starting from the interpolation points found by the IRKA algorithm. We then explore the relationship between potential theory in the complex plane and the optimal H_∞-norm interpolation points through several numerical experiments. The results of these experiments suggest that the optimal H_∞ approximation of order r yields an error system for which significant pole-zero cancellation occurs, effectively reducing an order n+r error system to an order 2r+1 system. These observations lead to a heuristic method for choosing interpolation points that involves solving a rational Zolatarev problem over a discrete set of points in the complex plane. / Master of Science