Den ökade konsumtionen i dagens samhälle leder till en större efterfrågan på nya råvaror. Samtidigt är jordens resurser begränsade och råvarupriserna höjs i samband med att resurserna håller på att ta slut. Därför är det viktigt att ta till vara på de resurser som finns genom att öka nyttjandegraden av material och sluta produkters livscykler, då kan materialet återvinnas och återanvändas vid tillverkning av nya produkter. Om tillverkande företag väljer att använda återvunnet material i sin produktion sparas jordens resurser in eftersom inte en lika stor mängd jungfruligt material behövs. Det bidrar till en ekologisk vinst som i vissa fall också kan leda till en ekonomisk vinst. Syftet med arbetet var att undersöka om materialåtervinningen kan göras ekonomiskt lönsam för de företag som väljer att sluta produkters livscykler och samla in returmaterialet. Detta genomfördes genom att undersöka vilka faktorer som påverkar den ekonomiska lönsamheten i värdekedjan och hur insamlingssystemet bör utformas för att maximera mängden insamlat installationsspill. För att kunna genomföra arbetet har vetenskaplig litteratur i form av rapporter och artiklar studerats för de ämnesspecifika områdena som studien behandlar, dessa stod till grund för rapportens teoretiska del. Sedan genomfördes en empirisk datainsamling i form av kvalitativ numerisk data, intervjuer hölls med golvläggare och logistikansvarig för extern returmaterialshantering. Utöver detta genomfördes observationer av uppvisade beteenden relaterat till insamling av installationsspill ute på byggarbetsplatser. En kvantitativ fältstudie genomfördes också som inkluderade respektive installationsprojekt. Resultatet av studien visar att generellt sätt är golvläggare positiva till att samla in returmaterial utan att företaget får betalt genom ekonomiska styrmedel så länge insamlingen inte medför något extra arbete. De resterande aktörerna i den omvända flödeskedjan har ett större ekonomiskt incitament än ett ekologiskt incitament till att medverka för att samla in returmaterial. Det försvårar för producenten att skapa en ekonomiskt lönsam returmaterialshantering då det skapas höga kostnader som produktens vinstmarginal ska klara av att täcka. Transport är den faktor som ackumulerar störst kostnad per insamlad enhet. För att sänka kostnaderna är det nödvändigt att returmaterial i höga kvantiteter och med hög kvalitet samlas in. Om ett företag lyckas skapa en lönsam returmaterialshantering kan det leda till minskade kostnader i form av material- och produktionskostnader. Resultatets betydelse från studien är viktig då det saknas studier som direkt behandlar och visar hur returmaterialshantering kan genomföras och göras ekonomiskt lönsam. Därmed bidrar studien till vidare diskussion och inspiration. Studien avgränsas till att analysera den ekonomiska lönsamheten av den externa returmaterialshanteringen. / The increased consumption in the modern society leads to a higher demand for new raw materials. At the same time, the earth's resources are limited and the prices increase when the resources decrease. Therefore, it is important to take advantage of the resources by increasing the utilization rate of material and close product lifecycles. The material can be recycled and reused in the manufacture of new products. If manufacturing companies choose to use recycled materials in their production the earth’s resources would be saved because less virgin material is needed. This contributes to an ecological profit which in some cases may also lead to a financial gain. The purpose of this work was to investigate whether recycling of materials could be economically profitable for the companies that choose to close product lifecycles and collect the end-of-use material. This was done by examining the factors that affect the economic viability of the value chain and how the collection system should be designed to maximize the amount of collected installation waste. In order to implement the work, scientific literature in the form of reports and articles are studied in the subject-specific areas that the study covers, these were the basis for the report's theoretical part. An empirical data collection was also done in the form of qualitative numerical data, interviews were held with flooring contractors and the logistics manager for external recycled material, and observations were conducted of exhibited behaviors related to the collection of installation waste out on construction sites. A quantitative field study was also conducted which included each installation project. The results of the study show that the flooring contractors are generally positive to collecting recycling material without any financial benefits as long as it does not involve any additional work. The remaining companies in the reverse supply chain have a higher financial incentive than an ecological incentive to participate and collect recycling material. This makes it difficult for the producer to create an economically viable collection system of recycling materials since it creates too high costs for the product's profit margin to be able to cover these costs. Transport is the factor that accumulates the highest cost per collected unit. To reduce the costs it is necessary to return material in high quantities and with high quality. If a company manages to create a profitable return of used materials it can lead to reduced costs in terms of material and production costs. The impact of the result is important because there are no or just a few previous studies that directly treat and show how a system of collecting recycling material can be implemented in a company and be economically viable. The study contributes to further discussions and inspiration. The study is limited to analyzing the economic viability of the external collection system of recycling material.

Introduktion: Under de senaste 20 åren har icke-tekniska färdigheters betydelse för patientsäkerheten belysts mer och mer i forskningen. Interprofessionell utbildning med CRM som simulatorkoncept används för att träna icke-tekniska färdigheter och teamarbete men att träna under pågående operation är ovanligt. Syfte: Syftet är att utvärdera hur deltagarna upplever användandet av icke-tekniska färdigheter under en interprofessionell lärandeaktivitet på en dagkirurgisk operation. Metod: Tvärsnittsstudie med enkät som deltagarna (N=239) blev tillfrågade att svara på efter deltagande vid operation. Enkäten utvärderas deltagarnas upplevelse av kommunikation och teamarbete. Deskriptiv statistik och analys med Chi2, Wilcoxon sign rank test och Kruskal-Wallis användes. Resultat: Användandet av kommunikation inom och mellan professionerna har rankats som mycket högt av majoriteten av deltagarna i alla frågor, vid kontroll med Chi2 analys är det statistiskt signifikanta svar. Deltagarna upplever en ökad förståelse för andra professioner i teamet efter deltagande och de flesta anser att de blir en mer effektiv medlem i teamet och samt att patienter har fördel av att ett team löser patientens problem. Ingen statistisk signifikant skillnad sågs mellan professionerna. Slutsats: Träning under en pågående operation är möjligt att genomföra samt är uppskattat av deltagarna och viktigt för deras utveckling av icke-tekniska färdigheter Nyckelord: Icke-tekniska färdigheter, interprofessionellt lärande, CRM, SBAR, closed-loop-kommunikation. / Introduction: During the past two decades, there has been increased interest in non-technical skills and how they affect patient safety. The number of articles published in the field has increased. Interprofessional education with the concept of CRM has been shown to be an effective way to train non-technical skills and teamwork, but training during ongoing surgery is uncommon.  Purpose: The purpose is to evaluate how the participants experienced the use of non-technical skills in an interprofessional learning activity during ambulatory surgery. Method: This was a cross-sectional study in which the participants (N=239) were asked to answer an evaluation survey following ambulatory surgery, concerning their experience of communication and teamwork. Descriptive statistics and inferential statistics with chi-square, Wilcoxon signed-rank test and Kruskal-Wallis were used to analyse the material.  Results: The use of communication within and between the professions was ranked as very high by the majority of the participants in all the questions in the survey, and control using chi-square showed the results to be statistically significant. The participants experienced an increased understanding of the other professions in the team, and deemed that they had become more effective team members. They were also of the opinion that patients have an advantage when a medical team solves their problems. There were no statistically significant results between the professions. Conclusion: Training can be implemented during ongoing surgery. This is a popular activity with participants, and is vital for their development of non-technical skills. Keywords: Non-technical skills, interprofessional education, CRM, SBAR, closed-loop communication

Bakgrund: På operationssalar samarbetar flera olika kompetenser mot ett gemensamt mål, att ge patienten god och säker vård och omvårdnad. Forskning har visat att det krävs ett gott teamarbete bland personalen för att patientsäkerheten ska kunna säkerställas.  Syfte: Syftet var att beskriva operationsteamets erfarenheter av vilka faktorer som påverkar teamarbetet på operationssal. Metod: Studien har genomförts med kvalitativ metod och induktiv ansats. Ett strategiskt urval användes som urvalsmetod. Två personer från varje yrkeskategori i teamet; anestesisjuksköterskor, anestesiologer, operationssjuksköterskor, operationsundersköterskor och operatörer handplockades till kvalitativa semistrukturerade intervjuer. Data har analyserats med kvalitativ innehållsanalys.  Resultat: Studien resulterade i sex huvudkategorier: Att samarbeta och ha en personlig relation till kompetenta kollegor, Att ha en god stämning där alla är inkluderade och känner sig trygga, Att vara väl förberedd, ha ett gemensamt mål och uttalade roller, Att vara fokuserad, engagerad och visa respekt även under stress, Att lyssna på varandra och kommunicera högt och tydligt med closed loop och Att arbeta strukturerat och använda de hjälpmedel och verktyg som finns.  Slutsats: Teamarbetet är viktigt för patientsäkerheten och för en god omvårdnad. Faktorer som samarbete, personliga relationer, en god stämning, gemensamma mål, respekt och kommunikation upplever operationsteamet påverkar teamarbetet. Faktorerna kan kännas självklara, samtidigt påtalar deltagarna den förbättringspotential som finns, vilket belyser det komplexa med teamarbetet.

The emergency nurse specialist provides advanced nursing care to critically ill patients in the emergency care setting. The resuscitation room at the emergency department is where critically ill patients are treated and cared for. It is fundamental for nurses to create an opportunity for patients to participate in their given care. Person centered care sees the person as an individual and requires nurses to work from the individual's need, and not only as a person with a medical condition. Including the patient in clinical decisions and making them a part of the team is vital for person centered care. Communication with the nurse specialist, patient and family is a necessary prerequisite for person centered care. Poor communication amounts to almost 70 percent of deviation rapports. Standardised means of communication amongst healthcare staff have been put in place to reduce these risks. The use of closed loop communication can have significant reductions in errors made when caring for critically ill patients. The aim of the study was to observe communication in the resuscitation room.  The study used a quantitative research design. Ten real-time observations were conducted at a tertiary teaching hospital in Stockholm, Sweden. Two observers were present in the resuscitation room using an observational sheet to document communication.  Closed loop communication was not seen to be used by all healthcare staff and was found to be dependent on the team working. Communication with the patient was the highest overall documented speech in the resuscitation room, which could suggest good patient participation.  The results show predominantly positive amounts of time spent communicating with the patient. Whereas closed loop communication was used equally as much as non-closed loop communication. / Sjuksköterskor med specialistutbildning inom akutsjukvård ger avancerad omvårdnad till kritiskt sjuka patienter i en akutvårdskontext. Kritiskt sjuka patienten ges omvårdnad och medicinsk vård på akutmottagningen i ett akutrum. Det är grundläggande för sjuksköterskan att i akutrummet skapa en möjlighet för patienten att vara delaktig i sin egen vård. Personcentrerad vård bidrar till det att skapa den möjligheten och är ett förhållningssätt där patienten ses som en individ med individuella behov och inte enbart som en person med en medicinsk åkomma. Att inkludera patienten i kliniskt beslutsfattande och göra den till en del av teamet är grundläggande inom den personcentrerade vården och kommunikationen mellan akutsjuksköterskan, patienten och familjen är av största vikt. Dålig kommunikation bidrar även till att patientsäkerheten försämras och 70 % av alla avvikelserapporteringar innefattar bristfällig kommunikation. Därför används standardiserad kommunikation mellan sjukvårdspersonal för att minska risken för bristfällig kommunikation. Användandet av closed loop kommunikation kan bidra till att kommunikationen vid vårdande av kritiskt sjuka patienter förbättras vilket minskar risken för misstag.  Syftet med studien var att observera kommunikation på akutrummet  Studien använde en kvantitativ forskningsdesign. Tio realtidsobservationer utfördes på ett akutsjukhus i Stockholm, Sverige. Två observatörer var närvarande på akutrummet och observerade kommunikation med hjälp av ett verktyg skapat för ändamålet.  Closed loop kommunikation användes inte av all vårdpersonal utan var beroende av vilket larmteam som tjänstgjorde. Andelen kommunikation med patienten var den högst mätta parametern gällande tal på akutrummet vilket skulle kunna tyda på god patientdelaktighet.  Resultatet visar en övervägande positiv andel tid som spenderas genom att kommunicera med patienten på akutrummet. Användandet av closed loop kommunikation var lika vanligt som kommunikation som inte kategoriseras som closed loop.

Bakgrund: Den snabba utvecklingen av avancerad diabetesteknik kräver god kunskap från diabetesteamet. Diabetessjuksköterskan ansvarar för utbildningen av ny teknologi med krav på säker och personcentrerad vård. Vid start av en hybrid closed loop insulinpumpbehandling inkluderar diabetessjuksköterskan generellt en representant från det företag som ansvarar för den avancerade insulinpumpen så att mottagaren ska få all teknisk information korrekt.  Syfte: Syftet med studien var att beskriva hur vuxna personer med diabetes typ 1 (T1D) upplever utbildningen utifrån säker och personcentrerad vård vid övergång till en hybrid closed loop insulinpumpbehandling. Metod: Kvalitativ intervjustudie med en induktiv ansats med semistrukturerade frågor genomfördes med åtta personer med T1D som har startat med en hybrid closed loop insulinpumpbehandling under åren 2020–2021. Intervjuerna hölls via zoom och de spelades in, transkriberades ordagrant och analyserades med en kvalitativ innehållsanalys. Resultat: Analysen resulterade i tre huvudkategorier och åtta underkategorier. Huvudkategorierna var: Tekniken och livet, Tekniken och utbildningen samt Tekniken och det professionella stödet. Det förekom tre olika typer av utbildningar; halvdag, tre dagar och distansuppstart, där majoriteten av deltagarna upplevde att de mottagit den utbildning de behöver för att känna sig trygg med behandlingen, men där vikten av snar uppföljning betonas. Insulinpumpföretagets support och diabetesteamets stöd är väsentliga för upplevelsen av trygghet. Slutsats: Den avancerade teknik som finns att tillgå idag förbättrar livskvaliteten och leder till ökad trygghet och frihet men kräver praktisk övning och snar uppföljning hos diabetessjuksköterska för att vara förenad med säker och personcentrerad vård. / Background: The rapid development of advanced diabetes technology requires great knowledge from the diabetes team. The diabetes nurse specialist is responsible for the education of new technology with demands for safe and person-centered care. When starting a hybrid closed loop insulin pump treatment, the diabetes nurse generally includes a specialist from the current company that is responsible for the advanced item, so that the receiver of the insulin pump is ensured to get all technical information correctly. Aim: The aim of this study was to describe how adult persons with diabetes type 1 (T1D) experience the education from the intention of safe and person-centered care in connection with transmission to a hybrid closed loop insulin pump treatment.  Method: Qualitative interview study with an inductive approach with semi structured interview questions were conducted with eight persons with T1D who have started with a closed loop insulin pump treatment during the years of 2020 and 2021. The interviews took place via zoom and were recorded, transcribed verbatim and analyzed using a qualitative content analysis. Results: The analysis resulted in three main categories and eight subcategories. The main categories were: Technique and life, Technique and education, Technique and the professional support. The result showed that there were three different kinds of education; half day, three days and distance start, where the majority of the participants experienced that they had received the education they needed to feel safe with the treatment, but where a close follow-up visit to the diabetes nurse specialist is crucial. Conclusion: The advanced technology that is available today, increases quality of life and leads to a sense of safety and freedom but demands practical training and a close follow-up visit to the diabetes nurse to be associated with safe and person-centered care.

Tunable antennas have emerged as a promising technology to address the challenges of achieving optimal performance across a wide range of frequencies. This abstract presents a study focused on designing and implementing an ideal antenna system design within a closed-loop system. Background. Tunable antennas offer a solution for achieving efficient signal transmission and reception over a broad spectrum. Traditionally fixed-frequency antennas have limitations in terms of bandwidth and efficiency, making them unfit for applications requiring adaptability to varying frequencies. The integration of tunable components in antenna systems results in greater flexibility and improved performance. Objectives. The main objective of this research is to evaluate and determine the ideal antenna design for closed-loop antenna systems which achieves maximum frequency coverage and efficiency. This involves the design of an architecture that seamlessly integrates components. Methods. The experimental methodology involves designing an antenna system design. The selected components are interconnected in a closed loop, allowing continuous monitoring and adjustment of the antenna’s characteristics. The Micro Controlling Unit (MCU) is programmed using the Arduino Integrated Development Environment (IDE), serves as the controller for managing the antenna tuner’s settings based on real-time feedback from the directional coupler and power detector. The bi-directional logic level converter ensures proper voltage compatibility between the MCU and the antenna tuner. Results. The results of the study showed that the proposed antenna system architecture was able to achieve the desired goals. The implemented closed-loop system demonstrates significant enhancements in frequency coverage and efficiency of the selected antenna. The antenna system was also able to maintain its efficiency even when the environment changed. Conclusions. The experimental results show that in closed-loop systems the performance of an antenna is optimised. The integration of the components enables dynamic frequency tuning, by enhancing the antenna’s maximum frequency coverage and efficiency. The results underscore the potential of tunable antennas in revolutionizing wireless communication systems, showing the way for more adaptable and high-performance devices in various applications.

Titel: Closed-loop supply chain: Implementering av utvecklat returflöde gällande begagnade handskar på HESTRA-Handsken AB. Kontext: Dagens konsumtions ökar allt mer då konsumenten ser stil och pris som en viktigare komponent än hållbarhet. För att istället öka produkters livslängd och minska dess miljöpåverkan kan en implementering av CLSC genomföras.  Syfte: I denna studie kommer CLSC att diskuteras utifrån textil- och läderindustrin. En fördjupning kommer att ske i HESTRA-Handsken AB:s omvända logistikprocess där skribenterna menar att komplettera denna. Studiens syfte blir därmed att identifiera hur företagets nuvarande returflöde kan utvecklas med målet att slutligen implementeras. Metod: Denna studie grundas i ett kvalitativt hermeneutiskt synsätt för besvarande frågeställning ett, samt en systematisk litteraturgranskning för att besvara frågeställning två. Empiriskt material har samlats in genom semi-strukturerade intervjuer där respondentvalidering har använts för att säkra att denna primärdata håller hög kvalitet. För att finna vetenskapligt granskade artiklar till teoriavsnittet har sökningar gjorts i databasen BSU. Vidare har mönsterjämförelse tillämpats för att analysera resultatet utifrån studiens frågeställningar. Resultat: Denna studie visar på att det finns potential hos HESTRA-Handsken AB att utveckla dess nuvarande returflöde. Studiens skribenter menar på att ett prisdiskrimineringsalternativ kan tillämpas för att öka inflödet av returer. Det finns ett intresse och engagemang hos ledningen till att utöka dess hållbarhetsprofil och detta är ett ypperligt exempel på det. Implementering är möjlig genom att antingen se till Dowlatshahis 11 förståelser för framgångsrik implementering, Lacys fem affärsmodeller eller Kirons fem innovationsmetoder. Bidrag: Studien bidrar med en litterär genomgång av ämnet CLSC och mer ingående returer samt återbruk. Sedermera ges praktiskt bidrag till HESTRA-Handsken AB, i form av förslag om hur dess nuvarande returflöde har potential att utvecklas och hur en implementering kan utformas. Slutligen kan andra företag, likt HESTRA-Handsken AB, se till denna studie för att tilldelas förslag kring hur dess returflöde kan utvecklas samt vad som bör beaktas vid en implementering av detta. Nyckelord: Closed-loop supply chain, returer, återbruk, begagnat, textil, läder / Title: Closed-loop supply chain: Implementation of developed return flow regarding used gloves at HESTRA-Handsken AB. Context: Today's consumption is increasing more and more as the consumer sees style and price as a more important component than sustainability. To increase the lifespan of products and reduce their environmental impact, an implementation of CLSC can be worth pursuing.  Purpose: The objective of this study is to investigate the CLSC based on the textile and leather industry. A deepened study will take in HESTRA-Handsken AB´s reverse logistics process, where the writers intend to supplement this. The purpose of the study will thus be to identify how the company's current return flow can be developed with the goal of finally being implemented.  Method: This study is based on a qualitative hermeneutic approach to being able to answer question one, as well as a systematic literature review to answer question two. Empirical material has been collected through semi-structured interviews where respondent validation has been used to ensure that this primary data is of high quality. To find peer reviewed articles for the theory section, searches have been made in the BSU database. Furthermore, pattern comparison has been applied to analyze the results based on the study´s questions.  Results: This study shows that there is potential at HESTRA-Handsken AB to develop its current return flow. The study´s authors believe that a price discrimination alternative can be applied to increase the inflow of returns. There is an interest and commitment on the part of management to expand its sustainability profile and this is an excellent example of this. Implementation is possible by either looking at Dowlatshahi´s 11 understandings of successful implementation, Lacy´s five business models, or Kiron´s five innovation methods.  Contribution: The study contributes with a literary review of the subject CLSC and focuses on returns and recycling. Furthermore, a practical contribution is given to HESTRA-Handsken AB, with suggestions on how their current return flow can be developed and how an implementation can be designed. Finally, other companies can look at this study to be assigned proposals on how its return flow can be developed and what should be taken into account when implementing this. Keywords: Closed-loop supply chain, returns, recycling, used, textile, leather

In this thesis, black-box models describing the quadcopter system dynamics for attitude control have been estimated using closed-loop data. A quadcopter is a naturally unstable multiple input multiple output (MIMO) system and is therefore an interesting platform to test and evaluate ideas in system identification and control theory on. The estimated attitude models have been shown to explain the output signals well enough during simulations to properly tune a PID controller for outdoor flight purposes. With data collected in closed loop during outdoor flights, knowledge about the controller and IMU measurements, three decoupled models have been estimated for the angles and angular rates in roll, pitch and yaw. The models for roll and pitch have been forced to have the same model structure and orders since this reflects the geometry of the quadcopter. The models have been validated by simulating the closed-loop system where they could explain the output signals well. The estimated models have then been used to design attitude controllers to stabilize the quadcopter around the hovering state. Three PID controllers have been implemented on the quadcopter and evaluated in simulation before being tested during both indoor and outdoor flights. The controllers have been shown to stabilize the quadcopter with good reference tracking. However, the performance of the pitch controller could be improved further as there have been small oscillations present that may indicate a stronger correlation between the roll and pitch channels than assumed.

Remanufacturing is an important product recovery option that benefits our sustainable development. Cores, i.e. the used products/parts, are essential resources for remanufacturing. Without cores, there will not be any remanufactured products. Challenges in the core acquisition process are mainly caused by the uncertainties of: return volume, timing and core quality. Core Acquisition Management actively attempts to reduce these uncertainties and achieve a better balance of demand and return for the remanufacturers. The aim of this dissertation is to extend the knowledge of Core Acquisition Management in remanufacturing, by investigating the current status of research and industrial practice, and developing quantitative models that assist the decision making in the core acquisition process. In the dissertation, a literature review is firstly conducted to provide an overview about the current research in Core Acquisition Management. Possible further research interests, for example, more studies based on non-hybrid remanufacturing systems and imperfect substitution assumption are suggested. Through an industrial survey carried out in a fast developing remanufacturing market - China, environmental responsibility and ethical  concerns, customer orientation and strategic advantage are identified as the most important motives for the remanufacturers, while customer recognition is their most serious barrier at present. Suggestions for further improving the Chinese remanufacturing industry from the policy-makers’ perspective are provided. After the above investigation, mathematical models are then developed to assist the acquisition decisions in two aspects: to deal with the uncertainties of return volume and timing, and to deal with the uncertainties of core quality. Acquisition decision about volume and timing is firstly studied from a product life cycle perspective, where the demands for remanufactured products and the core availability change over time. According to industrial observations, the remanufacturing cost decreases with respect to its core inventory. Using optimal control theory, core acquisition and remanufacturing decisions are derived to maximize the remanufacturer's profit. It is found that besides a simple bang-bang type control policy (either collecting as much as possible, or nothing), a special form of synchronizing policy (adjusting the core collection rate with demand rate) also exists. Furthermore, the acquisition decision depends greatly on the valuation of cores, and Real Option Valuation approaches are later used to capture the value of flexibility provided by owning cores when different aspects of remanufacturing environment are random. More specifically, the value of disposing a core earlier is investigated when the price of remanufactured product is uncertain, and the impact of the correlation between stochastic demand and return is also studied. To deal with the uncertainties of core quality, refund policies with different numbers of quality classes are studied. Under the assumption of uniformly distributed quality, analytical solutions for these refund policies are derived. Numerical examples indicate that the customers’ valuation of cores is an important factor influencing the return rates and the remanufacturer’s profit. Refund policies with a small number of quality classes could already bring major advantages. Credit refund policies (without deposits) are included for comparisons. In addition, within a game theory framework, the trade-off of two types of errors of the quality inspection in a deposit-refund policy is studied. The salvage values of different cores show great influences on the remanufacturer’s policy choices. The value of information transparency about the inspection errors are studied under different conditions. Interestingly, the customer may actually return more low quality cores when the inspection accuracy is improved.

Problem: The demand of beverages in PET bottles is constantly increasing. In this context, environmental, technological and regulatory aspects set a stronger focus on recycling. Generally, the reuse of recycled material from post-consumer PET bottles in bottle-to-bottle applications is seen as least environmentally harmful. However, closed-loop systems are not widely implemented in Europe. Previous research mainly focuses on open-loop recycling systems and generally lacks discussion about the current German and Swedish systems and their challenges. Furthermore, previous studies lack theoretical and practical enhancements for bottle-to-bottle recycling from a managerial perspective. Purpose: The purpose of this study is to compare the PET bottle recycling systems in Germany and Sweden, analyse the main barriers and develop enhancements for closed-loop systems. Method: This qualitative study employs a case study strategy about the two cases of Germany and Sweden. In total, 14 semi-structured interviews are conducted with respondents from different industry sectors within the PET bottle recycling systems. The empirical data is categorised and then analysed by pattern matching with the developed theoretical framework. Conclusion: Due to the theoretical and practical commitment to closed-loop recycling, the Swedish PET bottle recycling system outperforms the Germany system. In Germany, bottle-to-bottle recycling is currently performed on a smaller scale without a unified system. The main barriers for bottle-to-bottle recycling are distinguished into (1) quality and material factors, (2) regulatory and legal factors, (3) economic and market factors and (4) factors influenced by consumers. The enhancements for the systems are (1) quality and material factors, (2) regulatory and legal factors, (3) recollection factors and (4) expanding factors. Lastly, the authors provide further recommendations, which are (1) a recycling content symbol on bottle labels, (2) a council for bottle quality in Germany, (3) a quality seal for the holistic systems, (4) a reduction of transportation in Sweden and (5) an increase of consumer awareness on PET bottle consumption.