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A circular economy is a “closed-loop” system designed so that products flow back into the production cycle after use. With many companies implementing take-back programs as part of their sustainability strategy, a fundamental shift in consumption has occurred, with consumers considering disposal during and even before purchase decision-making. Twelve experiments reveal that consumers indicate a greater willingness to pay for circular program products. An increase in psychological ownership underlies the difference in product valuation. Specifically, the additional disposal control uniquely afforded by circular products increases the capacity of circular take-back program products to evoke psychological ownership. The process explanation is directly tested through mediation. Experimentally manipulating antecedents of psychological ownership (i.e., disposal control and expected ownership) provides further support for the conceptual framework.

Circular economy (CE) is seen as a strategy to achieve sustainable development, requiring commitment and support from multiple actors on all system levels; from companies and products to governments and nations. Circular business models (CBMs) are regarded as an important leverage to implement circularity at an organizational level, and business support is considered an important enabler of these. Communication between practitioners and policy-makers, as well as understanding the barriers of CE in the local context, can facilitate the development of efficient business support. This thesis has from a company perspective explored barriers to circular business model innovation (CBMI) and the impact of firm-specific business support activities on this innovation process. This was done through a multiple-case study of ten Swedish SMEs who had received direct business support for circularity, and thus had initiated a circular project. The study has identified seventeen different barriers across five categories, spanning over the entire innovation process from idea to full implementation. Overall, economic viability appears to be an important factor which relates to and depends on several other barriers, and the novelty of CE contributes to the occurrence of many identified challenges. While some barriers are more common across all ten cases, often challenges related to market demand, financing and knowledge, others are more specific for each case and circular strategy. Furthermore, this study has found that coaching, training, and funding are firm-specific activities that can help SMEs overcome mainly internal barriers in the early stages of the CBMI process, addressing several of the most common barriers identified in this study. This research has also included a company perspective on the costs and benefits of the activities, and pointed at important factors to consider in the development of future business support. / Cirkulär ekonomi ses som en strategi för att uppnå hållbar utveckling, och kräver engagemang och stöd från flertalet aktörer på samtliga systemnivåer; från företag och produkter till regeringar och nationer. Cirkulära affärsmodeller betraktas som en viktig hävstång för att implementera cirkularitet på en organisatorisk nivå, och företagsstöd anses vara en viktig möjliggörare av dessa. Kommunikation mellan utövare och beslutsfattare, samt förståelse för barriärer till cirkulär ekonomi i det lokala sammanhanget, kan underlätta utvecklandet av effektiva företagsstöd. Denna uppsats har ur ett företagsperspektiv utforskat barriärer till cirkulär affärsmodellsinnovation och den inverkan som företagsstöd har på denna innovationsprocess. Detta utfördes genom en fallstudie av tio svenska små och medelstora företag som mottagit stöd för cirkularitet, och som således initierat ett cirkulärt projekt. Studien har identifierat sjutton barriärer inom fem kategorier, vilka sträcker sig över hela innovationsprocessen från idé till full implementation. Generellt framträder ekonomisk livskraft som en viktig faktor, relaterad till samt beroende av flertalet andra barriärer, och nymodigheten i cirkulär ekonomi bidrar till förekommande av flera identifierade barriärer. Medan vissa barriärer är mer vanligt förekommande bland de tio fallen, ofta utmaningar relaterade till marknadens efterfrågan, finansiering och kunskap, är andra mer specifika för varje fall och cirkulär strategi. Vidare finner denna studie att rådgivning, träning och finansiering är företagsspecifika aktiviteter som kan hjälpa små och medelstora företag att överkomma huvudsakligen interna barriärer i de tidiga faserna av cirkulär affärsmodellsinnovation, och som bemöter flertalet av de vanligaste barriärerna som har identifierats i denna studie. Denna studie har även inkluderat ett företagsperspektiv på aktiviteternas nytta och kostnader, samt belyst viktiga faktorer att ta hänsyn till i utvecklingen av framtida företagsstöd.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24640号 / 工博第5146号 / 新制||工||1983(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 生越 友樹, 教授 松田 建児 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Yes / This paper presented a new circular polarization reconfigurable antenna for 5G wireless communications. The antenna, containing a semicircular slot, was compact in size and had a good axial ratio and frequency response. Two PIN diode switches controlled the reconfiguration for both the right-hand and left-hand circular polarization. Reconfigurable orthogonal polarizations were achieved by changing the states of the two PIN diode switches, and the reflection coefficient |S11| was maintained, which is a strong benefit of this design. The proposed polarization-reconfigurable antenna was modeled using the Computer Simulation Technology (CST) software. It had a 3.4 GHz resonance frequency in both states of reconfiguration, with a good axial ratio below 1.8 dB, and good gain of 4.8 dBic for both modes of operation. The proposed microstrip antenna was fabricated on an FR-4 substrate with a loss tangent of 0.02, and relative dielectric constant of 4.3. The radiating layer had a maximum size of 18.3 18.3 mm2, with 50 W coaxial probe feeding. / European Union’s Horizon 2020 research and innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424.

Yes / This paper presents a planar multi-circular loop antenna with a wide impedance bandwidth for next generation mm-wave systems. The proposed antenna comprises three circular rings with a partial ground plane with a square slot. The resonating structure is designed on a 0.254 mm thin RO5880 substrate with a relative permittivity of 2.3. The single element of the proposed design showed a resonance response from 26.5 to 41 GHz, with a peak gain of 4 dBi and radiation efficiency of 96%. The proposed multicircular ring antenna element is transformed into a four-element array system. The array size is kept at 18.25 × 12.5 × 0.254 mm3 with a peak gain of 11 dBi. The antenna array is fabricated and measured using the in-house facility. The simulated and measured results are well agreed upon and are found to be suitable for mm-wave communication systems.

The last few decades have seen an explosion in population growth and along with this growth we have also witnessed an increase in demand for products. Although our resources are limited, consumers' needs know no bounds. It is not surprising that we are also increasingly demanding more from our environment. It is therefore imperative that we make better use of our resources and reassess how we construe a product's lifecycle. Instead of a linear perspective, which typically follows a product's lifecycle from mining of raw materials to manufacturing, but then stops when products are trashed, we need to use a circular perspective, where we focus on the entire lifecycle of products, from not just manufacturing to usage, but also from usage to creation of new products through recycling. The focus of this dissertation is on understanding two important processes in the circular economy: that of usage and disposal. I focus on the role that consumers' product valuations play in these processes. In essay 1, I show that consumers value products made from recycled materials more than comparable regular products. I also document why this happens and demonstrate how this affects usage. In essay 2, I investigate the relationship between reuse and product disposal. The circular economy is based on what is now referred to as the 3R approach: reduce, reuse, and recycle. However, I show that consumers are more (vs. less) likely to trash products that they have used extensively (vs. rarely). This then leads to a conundrum: if we encourage consumers to reuse products extensively, it appears that they are more likely to trash them. It is therefore imperative that we understand this relationship better and find interventions to mitigate this negative relationship. / Doctor of Philosophy / The last few decades have seen an explosion in population growth and along with this growth we have also witnessed an increase in demand for products. To create a more sustainable world, it is imperative that we move towards a more circular economy, where we not only minimize waste, but also find ways to extract more use from our resources. One way to do this is to find ways to reuse products after they have reached the end of their lifecycle. The focus of this dissertation is on understanding two important processes in the circular economy: that of usage and disposal (essentially addressing questions about what to do with products that we no longer have a need for). I primarily focus on the role that consumers' product valuations play in influencing these processes. In essay 1, I study how consumers feel about products made from recycled materials. I find that consumers are willing to pay more for products made from recycled materials compared with products made from regular raw materials. The higher willingness to pay emerges because consumers value the process that transforms the recycled materials into brand new products. I also show that this valuation impacts use: consumers use products made from recycled materials more judiciously. In essay 2, I investigate the relationship between product usage and disposal. I find that when consumers use a product more extensively, they are more likely to trash the product compared with other forms of reuse, such as, disposing in the recycling bin, giving it to others, or reselling it. This effect emerges because when consumers use a product more frequently, they believe that the product has less value remaining for others, and a product that confers lower value to others should be trashed.

This thesis investigates the performance of a phased array of antenna elements conforming to a paraboloidal surface. We hypothesize that such a conformal phased array would have performance comparable to that of a correspondingly sized planar array. The performance of a paraboloidal array of antenna elements was simulated using an array program, and the resulting gains, side-lobe levels, and half-power beamwidths compared to those of a similarly sized planar array. Furthermore, we propose a beam-forming feed network for this paraboloidal phased array, and discuss the influence that coupling between the elements could have on the array performance. Lastly, we propose that such an array be used in conjunction with a parabolic reflector antenna to form a versatile hybrid antenna with several potential applications. / Master of Science