This thesis investigates the design and the performance of low-power microsensors that communicate directly to a satellite or a constellation of satellites. Information is spread using pseudo noise (PN) or Barker codes. The sensors use a single circular microstrip patch element with a wide beamwidth or a miniature phased array antenna that continuously scans to access the satellite(s). The array beam is controlled with a beam-forming network (BFN), which contains 3 or 4-bit phase shifters, which can be made in micro-electro-mechanical systems (MEMS) or in monolithic microwave integrated circuits (MMIC). The antennas are designed using array simulation program called 'ARRAY' and the results are used in another simulation program called Advanced Design System (ADS) to simulate the whole sensor package that uses one of the antennas. The simulation results show that a sensor as small as 2.35 cm in diameter is able to send information with data rate of 1 kbps at bit error rate less than 10?? to low-earth orbit (LEO) satellites with a transmitted power of 27.5 microwatts (-15.6 dBm). / Master of Science

Yes / Purpose: Circular economy is presented as an approach to economic growth that is in line with sustainable development. However, the recent literature has highlighted the limits of the concept in terms of environmental sustainability. The study examines the relationship between circular economy and conservation of ecosystems, using a case study on the implications of a circular economy for Slovak forests and forest sector. Design/methodology/approach: This study adopts a qualitative methodology through a focused review of the relevant literature on circular economy and sustainable development and primary data gathered through semi-structured interviews with 15 experts and practitioners in the forest sector, forest conservation and circular economy context, both from within as well as outside of Slovakia. Findings: The study finds that the forestry sector has an important role to play in a shift to a circular economy in Slovakia, with significant opportunities for improved efficiency as well as substitution of wood for non-renewable resources. There is also growing potential for ecosystem stewardship and restoration. However, the increased application of biomass could crowd out other needs, including for biodiversity. Safeguarding these services depends ultimately on good governance. Originality/value: The study highlights that circular economy taken in a narrow focus on resource efficiency is insufficient to ensure environmental sustainability but rather needs to be set within the broader environmental and social context.

Yes / Studies estimate that Africa's urban population is expected to triple over 40 years, from 395 million in 2010 to 1.339 billion in 2050. Challenges associated with increasing urbanisation and the rise of large cities in the African sub-region represent critical challenges to the environment and the rich ecosystem. The growing population, particularly in most cities in Africa, has resulted in increasing demand for non-degradable consumable waste products, changes in lifestyle and consumption patterns, and rising demand for transportation and associated solid waste disposal problems, especially tyre waste. However, few studies have examined circular economy practices such as tyre pyrolysis to attenuate Africa's ever-increasing waste disposal challenges. Moreover, most of these studies failed to account for specific risk-based decision-making attributes in an integrated way, such as technology readiness, risk identification, carbon footprint analysis, supply chain and procurement factors, and financial risk quantification. As a result, to the best of our knowledge and understanding, research-based tyre recycling feasibility practices are limited and scattered. We contribute to the literature by providing systematic literature on tyre pyrolysis in Africa from 2008-2022 inclusive, covering 16 African countries. To address tyre waste in Africa, this chapter provides a 10-point strategy on how pyrolysis can be integrated into production plants and associated businesses to minimise tyre waste in Africa. / The full-text of this article will be released for public view at the end of the publisher embargo on 29 July 2025.

Yes / Reviews and ratings of consumers towards a product impact consumer decision-making and their perceptions. Such information is key in measuring consumer satisfaction and net promoter scores. However, when the reviewed products are refurbished, consumer reviews become more important because information influences consumer behaviour and attitude toward looped products. This research explores the decision-influencing attributes of consumers while purchasing refurbished goods using quantitative and qualitative methods. Online after-sales 1986 laptop customers’ review and rating data in the public domain were analysed to reveal the decision-influencing attributes and their impact on potential consumers. The study envisions assisting the operations of sellers in the refurbished market by strengthening their businesses' value proposition and stimulating reverse logistics entrepreneurs to use the opportunity. Review data containing lifecycle valuation of old laptops induced feature extraction by machine learning applications. It is beneficial to sellers in the refurbished product segment. It provides information to strengthen their value proposition and is informative to entrepreneurs wanting to enter the segment. Based on the text analysis of consumer reviews, the study's results show that price, brand, design, performance, services, and utility influence consumers. The frequency analysis technique was used to extract attributes, followed by content analysis and feature selection using SHapley Additive exPlanations (SHAP) for exploring correlations between features and star ratings. Lastly, multinomial logistic regression was used to validate the generated model. The results show that brand, design, price, and utility are the most prominent attributes influencing consumers' decision-making with positive sentiments. In contrast, performance and services often generate neutral and negative sentiments. / The full-text of this article will be released for public view at the end of the publisher embargo on 27 Dec 2024.

The construction industry has a significant impact on the environment, and from the extractionof raw materials to the construction process to the operation and maintenance of buildings, eachphase contributes to environmental degradation in various ways. Consequently, promotingreuse in the Swedish building sector holds excellent potential for substantially reducing wastegeneration and CO2 emissions, aligning with broader sustainability objectives. We are tryingto create a circular economy paradigm where construction materials and resources are reused,remanufactured, and recycled, minimizing waste and environmental impact. However,realizing the full benefits of the Circular Economy requires significant changes in thinking andthe adoption of innovative business models. The project aims to identify barriers to the reuseof concrete in Sweden's construction sector, along with their causes and effects. A literaturereview was conducted to understand various barriers, forming the basis for subsequentinterviews with experts in a similar field, which is qualitative and semi-structured. Aninnovative collaboration project named Återhus helps to facilitate a comprehensive approach,exploring the challenges hindering reuse practices to inform strategies to overcome thesebarriers and promote greater reuse. The overall results, analysis, and discussion from all thesestudies reinforce the comparison of the views and experiences of different stakeholder groupsand how these differences affect the overall implementation of reuse in construction. Theseinterviews identified barriers and grouped them into the following categories: standardization,economic, material handling, knowledge, and technical barriers. Many barriers are highlyinterconnected, and multiple connections were found within knowledge within the market, aswell as a lack of standardization within the people's knowledge, culture, and understandingtoward a new transition of circularity for reuse.

This thesis investigates the role of industrial design in promoting sustainability and circular economy principles, particularly through collaboration with PaperShell AB, a company specializing in sustainable composites. The study focuses on developing a circular bio-economy system that integrates local mycelium cultures for material decomposition and soil regeneration. The central research question is: How can industrial design practices evolve to foster ecological regeneration while maintaining economic viability? Key findings emphasize the importance of closing material loops and reimagining industrial processes to harmonize with ecological systems. The Catifa Carta project, a collaboration with the Italian furniture brand Arper, serves as a case study demonstrating the practical application and success of these principles. Future research directions include exploring the scalability of these practices and additional ecological partnerships.

Yes / The increase in pharmaceutical waste medicines is a global phenomenon and financial burden. The Circular Economy, as a philosophy within the pharmaceutical supply chain, aims to promote waste reduction, maximise medicines value, and enable sustainability within this supply chain (increasing circularity). Circularity strategies for pharmaceuticals are not currently implemented in many countries, due to quality and safety barriers. The aim of this study was to determine whether the application of circular economy principles can minimise pharmaceutical waste and support sustainability in the pharmaceutical supply chain; Methods: a detailed narrative literature review was conducted in order to examine pharmaceutical waste creation, management, disposal, and the application of circular economy principles; Results: the literature scrutinised revealed that pharmaceutical waste is created by multiple routes, each of which need to be addressed by pharmacists and healthcare bodies through the Circular Economy 9R principles. These principles act as a binding mechanism for disparate waste management initiatives. Medicines, or elements of a pharmaceutical product, can be better managed to reduce waste, cost, and reduce negative environmental impacts through unsafe disposal. the study findings outline a Circular Pharmaceutical Supply Chain and suggests that it should be considered and tested as a sustainable supply chain proposition.

This thesis investigates the implementation of circular economy principles in plastic waste management, focusing on challenges and strategies within the European context. The study highlights the significance of CE in transforming the plastic industry by promoting resource efficiency, waste reduction, and systemic collaboration among stakeholders. It explores the theoretical foundations of CE, the 9R framework, and waste hierarchy, alongside European regulations such as the Packaging and Packaging Waste Directive, the Waste Framework Directive, and the Circular Economy Action Plan. Through a comparative analysis of two companies, one in Germany and one in Sweden, the research examines the diverse approaches to plastic waste management, emphasizing the role of regulatory compliance, partnerships, and consumer engagement. The findings reveal that while both companies are committed to circularity, their strategies differ based on market position, operational context, and customer dynamics. The study identifies key obstacles, such as inefficiencies in recycling systems, consumer behavior, and regulatory challenges, that hinder the full realization of CE principles. The thesis underscores the importance of interdisciplinary collaboration, innovative solutions, and robust policy frameworks in advancing CE transitions. It is concluded that, although CE provides a promising framework for addressing plastic waste, achieving its full potential requires focused efforts across multiple sectors. Recommendations for future research include expanding case studies, exploring specific supply chain stages, and examining the long-term effectiveness of CE initiatives.

Secreted phospholipase A2 (PLA2) is an interfacial enzyme that catalyzes the calcium-dependent hydrolysis of glycerophospholipids to free fatty acids and lyso-phospholipid, which are further converted to eicosanoids and platelet activating factor with broad biological activities. PLA2 is inactive in solution, but undergoes interfacial activation upon binding to biological membranes. Despite extensive studies on secreted PLA2s, the structural basis for interfacial activation and the effects of site-directed mutations remain largely uncharacterized. Two mutants of human group IIA PLA2, with tryptophans incorporated at the 3rd or 5th position in the N-terminal helix, display dramatic differences in activity compared to the wildtype enzyme. This project analyzes the distinct structural changes that occur in PLA2 and two Trp-mutants during interfacial activation, which are responsible for the observed disparities in activity. Additionally, the thermal stability of both mutants was determined in order to explore possible correlations between resistance to thermal denaturation and enzymatic activity. The V3W mutant shows enhanced activity and a higher optimal temperature compared to the wildtype, which may be promoted at least partially by the high affinity of tryptophan for the lipid-aqueous interface. Contrastingly, the FSW enzyme, which has a tryptophan within the substrate-binding pocket, displays greatly diminished activity compared to both the wild-type and V3W mutant, suggesting inefficient loading of substrate. Circular dichroism and fluorescence studies reveal that the differences in activity of the mutants result from distinct structural changes upon activation. Furthermore, thermal denaturation of V3W was partially reversible, whereas F5W showed no recovery of secondary structure following decrease of temperature. Thus, tryptophan incorporation at two close positions modulates the activity of PLA2 in strikingly different ways, which are associated with defined changes in the secondary structure and the thermal stability of the enzyme. Our results may find industrial or pharmaceutical applications, such as production of fatty acids or development of antibacterial agents.

The society today lives on the philosophy of ‘take-make-use-dispose.’ In the long run, this is not sustainable as the natural resources and the waste carrying capacity of the earth are limited. Therefore, it is essential to reduce dependency on the natural resources by decoupling the growth from the consumption. In this venture, both the society and the manufacturing industry have a vital role to play. The society needs to shift towards Circular Economy that rests upon the philosophy of ‘take-make-use-reuse’ and the manufacturing industry has to be a major stakeholder in this shift. Despite being proven to be both economically and environmentally beneficial, successful examples of circular systems are few today. This is primarily due to two reasons; firstly, there is a lack of systemic and systematic approach to guide industries and secondly, there is a lack of analysis methods and tools that are capable of assessing different aspects of circular manufacturing systems. Taking on to these challenges, the objective of this research is to bring forward a framework with methods and decision support tools that are essential to implement circular manufacturing systems. The initial conceptual framework with the systemic approach is developed based on extensive review and analysis of research, which is further adapted for industrial implementation. Systematic analysis methods, decision support and implementation tools are developed to facilitate this adaptation. This development has been supported by four cases from diverse manufacturing sectors. Behind each decision support tool, there are analysis methods built upon mainly system dynamics principles. These tools are based on simulation platforms called Stella and Anylogic. Among other things, these tools are capable of assessing the performance of closed-loop supply chains, consequences of resource scarcity, potential gains from resource conservation and overall economic and environmental performance of circular manufacturing systems. / <p>QC 20170522</p> / ResCoM: Resource Conservative Manufacturing- transforming waste into high value resource through closed-loop product systems