• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6
  • 4
  • 3
  • 2
  • 1
  • Tagged with
  • 34
  • 34
  • 19
  • 14
  • 11
  • 9
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 8
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Sistema de reciclagem de veículos em final de vida : uma proposta ambientalmente mais sustentável para o cenário brasileiro

Coimbra, Núbia dos Santos January 2017 (has links)
A escassez de sistemas consolidados de reciclagem de veículos no Brasil e o grande volume de veículos em final de vida (VFVs) junto aos pátios do Departamento Estadual de Trânsito do Rio Grande do Sul - DETRAN/RS serviram de base para o desenvolvimento desta dissertação. Em face disso, o objetivo deste trabalho foi desenvolver um sistema de reciclagem de VFVs ambientalmente mais sustentável, a partir de exemplos globais de melhores práticas adotadas, atendendo à legislação vigente do país. Para tanto, a presente dissertação é composta por dois estudos fundamentados em revisões sistemáticas e em estudos de caso. Inicialmente, como resultado da primeira revisão sistemática, foi realizada a comparação de sistemas de gestão de reciclagem de veículos, identificados em 25 países. Essa comparação possibilitou ampliar o conhecimento de tecnologias e de procedimentos adotados em diferentes realidades, permitindo a proposição de oito políticas a serem adotadas em âmbito nacional, bem como três ações de melhoria ao atual sistema do DETRAN/RS. Em seguida, a segunda revisão sistemática permitiu a proposição de um sistema ambientalmente adequado para reciclagem de VFVs, que sirva de base para a futura padronização de processos de reciclagem, visando a potencial criação de centros especializados em reciclagem de veículos (CERVs). Diante do exposto, os resultados da pesquisa demonstraram que o tema da reciclagem de veículos está inserido num cenário mais amplo, necessitando da participação de todos os stakeholders envolvidos no processo, a exemplo: (i) das montadoras e fabricantes de peças, no desenvolvimento de tecnologias automotivas; (ii) dos entes federados, na criação de legislações mais rígidas e específicas, com foco na economia circular; e (iii) da sociedade na busca de produtos eco-amigáveis. Por fim, conclui-se que, associado às políticas e ações de melhoria sugeridas, a adoção do sistema ambientalmente adequado para reciclagem de VFVs proposto, poderá acelerar a criação de um ambiente favorável para o desenvolvimento e a consolidação da reciclagem no país. / The scarcity of consolidated vehicle recycling systems in Brazil and the huge amounts of endof- life vehicles (ELVs) at the Transit State Department of Rio Grande do Sul - DETRAN/RS courtyards served as the basis for the development of this Masters dissertation. Therefore, the objective of the work was to develop an environmentally more sustainable ELVs recycling system, based on global adopted best practices, without disregarding the country's current legislation. So, this dissertation is composed of two studies based on systematic reviews and on case studies. Initially, as a result of the first systematic review, a comparison of vehicle recycling management systems was carried out, identified in 25 countries. This comparison allowed the increasing of the knowledge about technologies and procedures adopted in different realities, making possible a proposal of educational policies to be adopted at national level, as well as three improvement actions for the current system of the DETRAN/RS. Subsequently, a second systematic review allowed a proposal for a suitable environmentally recycling system for the ELVs, which serves as the basis for a standardization of recycling processes, aiming the potential creation of specialized centers for such processes (CERVs). Considering this, the research results showed that the theme of product recycling is inserted in a broader scenario, requiring participation of all stakeholders involved in the process, such as: (i) the automakers and parts manufacturers, in the automotive technologies development; (ii) the federal entities, in the creation of more rigid and specific legislation, focusing on the circular economy; and (iii) the society in the search for eco-friendly products. Finally, it is concluded that, associated with the suggested policies and improvement actions, the adoption of the proposed environmentally appropriate system for the recycling of the ELVs, may accelerate the creation of a favorable way to the develop and consolidate the recycling in our country.
12

Sistema de reciclagem de veículos em final de vida : uma proposta ambientalmente mais sustentável para o cenário brasileiro

Coimbra, Núbia dos Santos January 2017 (has links)
A escassez de sistemas consolidados de reciclagem de veículos no Brasil e o grande volume de veículos em final de vida (VFVs) junto aos pátios do Departamento Estadual de Trânsito do Rio Grande do Sul - DETRAN/RS serviram de base para o desenvolvimento desta dissertação. Em face disso, o objetivo deste trabalho foi desenvolver um sistema de reciclagem de VFVs ambientalmente mais sustentável, a partir de exemplos globais de melhores práticas adotadas, atendendo à legislação vigente do país. Para tanto, a presente dissertação é composta por dois estudos fundamentados em revisões sistemáticas e em estudos de caso. Inicialmente, como resultado da primeira revisão sistemática, foi realizada a comparação de sistemas de gestão de reciclagem de veículos, identificados em 25 países. Essa comparação possibilitou ampliar o conhecimento de tecnologias e de procedimentos adotados em diferentes realidades, permitindo a proposição de oito políticas a serem adotadas em âmbito nacional, bem como três ações de melhoria ao atual sistema do DETRAN/RS. Em seguida, a segunda revisão sistemática permitiu a proposição de um sistema ambientalmente adequado para reciclagem de VFVs, que sirva de base para a futura padronização de processos de reciclagem, visando a potencial criação de centros especializados em reciclagem de veículos (CERVs). Diante do exposto, os resultados da pesquisa demonstraram que o tema da reciclagem de veículos está inserido num cenário mais amplo, necessitando da participação de todos os stakeholders envolvidos no processo, a exemplo: (i) das montadoras e fabricantes de peças, no desenvolvimento de tecnologias automotivas; (ii) dos entes federados, na criação de legislações mais rígidas e específicas, com foco na economia circular; e (iii) da sociedade na busca de produtos eco-amigáveis. Por fim, conclui-se que, associado às políticas e ações de melhoria sugeridas, a adoção do sistema ambientalmente adequado para reciclagem de VFVs proposto, poderá acelerar a criação de um ambiente favorável para o desenvolvimento e a consolidação da reciclagem no país. / The scarcity of consolidated vehicle recycling systems in Brazil and the huge amounts of endof- life vehicles (ELVs) at the Transit State Department of Rio Grande do Sul - DETRAN/RS courtyards served as the basis for the development of this Masters dissertation. Therefore, the objective of the work was to develop an environmentally more sustainable ELVs recycling system, based on global adopted best practices, without disregarding the country's current legislation. So, this dissertation is composed of two studies based on systematic reviews and on case studies. Initially, as a result of the first systematic review, a comparison of vehicle recycling management systems was carried out, identified in 25 countries. This comparison allowed the increasing of the knowledge about technologies and procedures adopted in different realities, making possible a proposal of educational policies to be adopted at national level, as well as three improvement actions for the current system of the DETRAN/RS. Subsequently, a second systematic review allowed a proposal for a suitable environmentally recycling system for the ELVs, which serves as the basis for a standardization of recycling processes, aiming the potential creation of specialized centers for such processes (CERVs). Considering this, the research results showed that the theme of product recycling is inserted in a broader scenario, requiring participation of all stakeholders involved in the process, such as: (i) the automakers and parts manufacturers, in the automotive technologies development; (ii) the federal entities, in the creation of more rigid and specific legislation, focusing on the circular economy; and (iii) the society in the search for eco-friendly products. Finally, it is concluded that, associated with the suggested policies and improvement actions, the adoption of the proposed environmentally appropriate system for the recycling of the ELVs, may accelerate the creation of a favorable way to the develop and consolidate the recycling in our country.
13

An Improved Airflow and Watering Balance for a Biowall

Dhanurja De Silva (16650390) 07 August 2023 (has links)
<p>Clean indoor air is a necessity, in the past opening a window or supplying outdoor air would suffice for removing indoor contaminated air. As humans live in more dense neighborhoods or urban areas, the need for energy efficient clean indoor air is important. As outdoor air pollution increases, a Biowall is a device to improve aesthetics and clean indoor air by pulling air through the root zone of plants in a loosely packed growth media. The Biowall is a sustainable supplement to a single use air filter. For this research a small Biowall was designed, fabricated, tested, and installed in the Children’s wing of a public library. The airflow simulation and watering for the Biowall was explored using Autodesk CFD to simulate the airflow through growth media and identify a hole pattern to distribute airflow evenly through the plant trays. Various watering line designs were also tested until the rectangular design proved to be more balanced at distributing the water evenly to the growth media. Finally, the air cleaning ability of the Biowall was tested using a Clean Air Delivery Rate (CADR) test to quantify the cleaning rate. The Biowall provided 12 cfm of clean air, or about 2 cfm/sq ft of plant tray area.  </p>
14

Replacement of Lead in a Norma Precision AB Hunting Bullet

Petersson, Christopher, Klara, Trydell January 2017 (has links)
No description available.
15

Miljömässigt hållbara konsumenter och deras avståndstagande mot tidsbegränsade erbjudanden på Instagram / Environmentally sustainable consumers and their distancing to time-limited offers on Instagram

Tegstam, Emma, Carlsson, Elin January 2021 (has links)
The development of social media has lead to major changes in marketing. Today, there are so called influencers who through their social channels can convey advertising to its followers. When an influencer publishes advertising material, they often contain an offer, and it is not uncommon for these offers to be limited in time, meaning the offer is only available for a certain period of time. With this development, there is also an increasing focus on the environment, sustainable development and consumers' responsibility in counteracting negative environmental effects, for example as a result of consumption. Based on this background, the purpose was designed to find out to what extent environmentally sustainable consumers are affected by time-limited offers that are marketed by influencers on Instagram. Environmentally sustainable consumers have been defined in the study as people who have a negative view of consumption. For this purpose three research questions were created which were examined in a survey. The respondents' answers were tested by regression analyzes. The results showed acceptance of all hypotheses. 1) Time-limited offers published by influences on Instagram lead to increased consumption, 2) an environmentally sustainable attitude has a negative effect on consumption and 3) time-limited offers published by influencers on Instagram lead to a negative effect on consumption, when the consumer has an environmentally sustainable attitude. The results of the study can then be related to several different theories from previous research, such as impulse buying, stimuli, collectivism /individualism, the SOR-model, the source credibility theory and halo effect theory. The study contributes to a greater understanding of consumers' relationship with an environmentally sustainable attitude to time-limited offers, which are published by influencers on Instagram. The result can be useful for companies that work with influencers when designing time limited offers. (This paper is written in Swedish) / Sociala mediers framväxt har fört med sig stora förändringar avseende marknadsföring. Idag finns så kallade influencers som genom sina sociala kanaler kan förmedla reklam till sinaföljare. När en influencer publicerar reklaminlägg innehåller dem ofta något erbjudande och det är inte ovanligt att dessa erbjudanden är tidsbegränsade, det vill säga att erbjudandet endast finns tillgängligt under en bestämd tidsperiod. I takt med denna utveckling riktas också allt mer fokus på miljö, hållbar utveckling och konsumenters ansvar i att motverka negativa miljöeffekter till följd av exempelvis konsumtion. Mot denna bakgrund utformades syftet som var att ta reda på i vilken grad miljömässigt hållbara konsumenter påverkas av tidsbegränsadeerbjudanden som marknadsförs av influencers på Instagram. Miljömässigt hållbara konsumenter har i studien definierats som personer som har en negativ syn på konsumtion. Till syftet formulerades tre frågeställningar som undersöktes i en enkätundersökning. Respondenternas svar redovisades genom regressionsanalyser. Resultatet visade acceptans för samtliga hypoteser. 1) Tidsbegränsade erbjudanden utgivna av influencers på Instagram leder till ökad konsumtion, 2) en miljömässigt hållbar inställning har en negativ effekt på konsumtion och 3) tidsbegränsade erbjudanden utgivna av influencers på Instagram leder till en negativ effekt på konsumtion, när konsumenten har en miljömässigt hållbar inställning. Studiens resultat kunde därefter relateras till flera olika teorier från tidigare forskning som exempelvis impulsköp, stimuli, kollektivism/ individualism, SOR-modellen, source credibility theory och halo effect theory. Studien bidrar till en större förståelse för vilken relation konsumenter med en miljömässigt hållbar inställning har till tidsbegränsadeerbjudanden, som är utgivna av influencers på Instagram. Resultatet kan tänkas vara användbart för företag, som arbetar med influencers, vid utformning av tidsbegränsadeerbjudanden.
16

E-handelsföretags utmaningar inom logistikhantering : En kvalitativ studie om hur en ökad miljömedvetenhet och krav på korta leveranstider sätter press på e-handelsföretags logistikhantering

Adolfsson, Eric, Sandberg, Marius January 2020 (has links)
Bakgrund: Det miljömässiga hållbarhetstänket är en drivande faktor inom logistikutvecklingen i samband med de påtryckningarna från både samhället och dess konsumenter. Den kraftiga tillväxten inom e-handeln har satt e-handlare i en svår situation då kraven på korta leveranstider påverkar deras arbete med att även arbeta mer miljömässigt hållbart. Här sätts företagens logistikhantering på prov, då dilemmat mellan leveranstider och miljömässigt hållbara leveranser tvingar företagen att hitta en balans mellan de två. Därmed påvisas det att e-handelsföretagens arbete med sin logistikhantering blir deras sätt att överkomma denna problematik. Syfte: Syftet med denna studie är att bidra till en ökad förståelse kring hur ehandelsföretag arbetar med sin logistikhantering för att hålla sig konkurrenskraftiga. Frågeställning: 1) Hur påverkar efterfrågan av miljömässigt hållbara transportlösningar e-handelsföretags logistikhantering? 2) Hur arbetar e-handelsföretag med sin logistikhantering för att möta efterfrågan på korta leveranstider? Metod: Studien har en kvalitativ forskningsstrategi och genom en flerfallsstudie har fyra fallföretag valts att studeras. Det perspektiv som valdes inom studien är det hermeneutistiska perspektivet med en abduktiv ansats. Insamlingen av empirin har skett med hjälp av fyra semistrukturerade intervjuer med en respondent från respektive fallföretag. Den empiriska data har även kompletterats med dokumentstudier Slutsats: Från studien kunde vi komma till slutsatsen att e-handelsföretags arbete med att erbjuda miljömässigt hållbara leveranser härstammade från flera faktorer. Där valet att outsourca sina godstransporter och ett ökat användande av hemleveranser i kombination med allt mer automatiserade och information-drivna lagerverksamheter var deras sätt att möta denna efterfrågan. Då dilemmat med att arbeta miljömässigt hållbart inte alltid korrelerar med e-handelsföretagens ambitioner att erbjuda korta leveranstider visade det sig att områden som fyllnadsgrad var en aspekt där leveranstid visade sig vara viktigare och därav fortsätter e-handlare att behålla sina låga fyllnadsgrader. Bortsett från fyllnadsgrader är automatisering och användandet av informationssystem områden där miljömässigt hållbara leveranser och korta leveranstider korrelerade. / Background: The environmental sustainability concept is a driving factor in the development of logistics in connection with the pressures from both society and its consumers. The strong growth in e-commerce has put e-retailers in a difficult situation as the requirements for short delivery times affect their work to work even more environmentally sustainable. Here, companies logistics management is put to the test, as the dilemma between delivery times and environmentally sustainable deliveries forces the companies to strike a balance between the two. Thus, it is demonstrated that the e-commerce companies work with their logistics management becomes their way of overcoming this problem. Purpose: The purpose of this study is to contribute to a better understanding of how e-commerce companies work with their logistics management to stay competitive. Research question: 1) How does the demand for environmentally sustainable transport solutions affect e-commerce companies' logistics management? 2) How does e-commerce companies work with their logistics management to meet the demand for short delivery times? Methodology: The study has a qualitative research strategy and through a case study, four case companies have been selected to study. The perspective chosen within the study is the hermeneutic perspective with an abductive approach. The collection of the empirical data was conducted using four semi-structured interviews with one respondent from each case company. The empirical data has also been supplemented with document studies Conclusion: From the study, we were able to conclude that the e-commerce companies efforts to offer environmentally sustainable deliveries can be derived from several factors. Where the choice to outsource their freight transport and increased use of home deliveries in combination with increasingly automated and information-driven warehousing operations was their way of meeting this demand. As the dilemma of working in an environmentally sustainable manner does not always correlate with the ambition of e-commerce companies to offer short delivery times, it was found that areas such as fill rates were an aspect where delivery time proved to be more important and hence e-retailers continue to maintain their low fill rates. Apart from filling levels, automation and the use of information systems are areas where environmentally sustainable deliveries and short delivery times are correlated.
17

HOUSEHOLD MANAGEMENT OF CONSUMER ELECTRONICS IN THE UNITED STATES

Matthew Joseph Bih Gozun (13119435) 19 July 2022 (has links)
<p>    </p> <p>Electronic waste is one of the fastest growing waste streams, spurred by their rising market and demand. However, these devices contain an array of metals that is recyclable for economic and environmental benefit through secondary manufacturing. As the turnaround rate for newer models quickens, consumers are motivated to purchase novel devices, leaving their current ones behind. Focusing on how United States (U.S.) households manage their electronics, a top-down approach stock and flow STELLA model was created to model the lifecycle of eight common electronics. Input data for the model came from a public online survey directed to U.S. household owning adults. From the model, a metallic stock and flow analysis was conducted to quantify the trends, environmental footprint, and economic value of stored devices in U.S. households and how it compares to devices being used, disposed, and recycled. The number of stored devices in the U.S. was found to be increasing annually with a stored amount of over 757 million stored individual electronic devices, nearly half of which originate from cell phones, carrying an economic value of 32.6 billion US dollars (USD) and carbon emissions of 7.6 billion kilograms (kg) from their metallic components alone for the year 2020. Most of the pollution and economic value stems from precious metals (PMs) and in a circular economy, these stored metals can have a significant impact to the environment and economy through recycled. Also, with advancing capabilities of smartphones, the metallic composition for device components of Samsung galaxy smartphones was quantified to assess their evolving metallic content. With the growing market of electronic devices, knowing the value and importance of devices currently in U.S. households is critical. This underlies the influence of sustainable design through a circular economy to push initiatives to manufacture recyclable friendly devices, expand the metal recycling industry, and motivate citizens to properly handle their stored devices. </p>
18

Characterizing quantity and physical dimensions of consumer electronic devices: A pilot study of Indiana households

Juliette Fernada Bermudez Camelo (12797204) 01 August 2023 (has links)
<p>To accurately estimate the potential recovery of metals from electronic devices, various tools such as mass flow analysis, dynamic models, and forecasting models have been employed. However, the reliability of the model-generated outputs hinges on the accuracy of the input data. To ensure accurate data collection, it is imperative to examine and compare different methodologies. Although surveys have conventionally been used in information and telecommunications technologies to gather consumer information, their validity is seldom contrasted with alternative methods due to the lack thereof. In response, a new mixed methodology has been developed to obtain primary consumer data through tangible information, offering new avenues for data acquisition. The methodology involves quantitative and qualitative approaches taking direct physical measurements (dimensions, weight, and quantity) of devices and including a ten question semi-structured interview to discussed consumer devices use, stock and transfer patterns, composition changes of the electronic devices, and disposal behavior. As a result, it was found new methodology measured 79% of the devices directly at laboratories and 21% of the remaining devices were self-reported by the participant. The devices on consumer stage frequently have the same type and number of components as fabric and a positive difference of about 17.99 g compared with the mass reported by fabricants or literature. The sequential steps undertaken by participants in the new methodology to acquire consumer-stage data offer distinct advantages over surveys, particularly in capturing a more comprehensive inventory of devices in storage.</p><p>Additional results indicate that the proposed methodology can provide valuable insights into the stock of electronic devices. Nevertheless, further research is required to understand the implications of surveys versus direct measurements in accurately representing mass flows during the user stage. Additionally, the relevance of external power supply or charging systems on storage will be explored as part of the supplementary findings. By improving the accuracy of metal recovery estimation and exploring more effective data collection methods, we can optimize closed-loop projects and contribute to sustainable resource management.</p>
19

Novel Microplastics Remediation Strategy Using High-Voltage Atmospheric Cold Plasma

Juan Velasquez (15353575) 27 April 2023 (has links)
<p>  </p> <p>Plastics are the most common polymers used in various industries. However, million tons of plastics are produced and disposed every year around the world, and part of them end up entering the environment and agricultural ecosystems in the form of microplastics. Microplastics have become an environmental and health threat to aquatic species and humans because they are small and can easily reach water bodies for municipal and agricultural uses. Microplastics have been traced in food commodities and products derived from animals and even found in bottles of drinking water. As an approach to permanently remediating microplastics, current microplastic degradation techniques, however, require high energy inputs and thus are generally not cost-efficient. High-voltage atmospheric cold plasma (HVACP) is a low-cost energy-efficient technology to produce highly reactive species that can induce physicochemical changes in polymers. This study, for the first time, used HVACP as a novel remediation strategy for microplastics. HVACP was generated by dielectric barrier discharge at 50 kV using oxygen, nitrogen, or their mixture as working gas. Two types of microplastics, polypropylene (PP) and low-density polyethylene (LDPE), were treated for 30 min, and the effect of 24-h post-treatment was also studied. The properties of HVACP-treated microplastics, including weight, particle size, crystallinity, melting point, carbonyl index (CI), and surface morphology, were comprehensively analyzed. HVACP treatments were found effective in degrading both PP and LDPE microplastics. A larger extent of degradation was observed with PP microplastics treated by O/N mixture plasma, but the nitrogen plasma-treated sample showed a higher degree of oxidation according to its CI. For PE microplastics, oxygen plasma caused more degradation, but post-treatment did not promote further oxidation. The results indicated two potential mechanisms for microplastic degradation by HVACP. LDPE microplastics were degraded by oxidative reactions caused by highly reactive oxygen species, and PP microplastics followed a hydrolytic pathway of degradation as they became more hydrophilic after HVACP treatment. This study proved that HVACP is a promising method for microplastic degradation, and thus has great potential for addressing the severe challenges of microplastics that the food and agriculture sectors are currently facing.</p>
20

ENHANCING INTERPRETABILITY AND ADAPTABILITY OF MANUFACTURING EQUIPMENT HEALTH MODELS AND ESTABLISHMENT OF COST MODELS FOR MAINTENANCE DECISIONS

Haiyue Wu (15100972) 05 April 2023 (has links)
<p>  </p> <p>The integration of Industry 4.0 technologies such as cyber-physical systems, the internet of things, and artificial intelligence has revolutionized the traditional manufacturing systems, making them smart and digital. Maintenance, a critical component of manufacturing, has been incorporated with data-driven strategies such as prognostic and health management (PHM) to improve production efficiency and reliability. This is achieved by real-time sensing and AI-based modeling, which monitor the health condition of operational equipment for fault detection or failure prediction. The results generated by these models provide crucial support for decision-making processes in manufacturing, ranging from maintenance scheduling to production management.</p> <p>This research focuses on data-driven machine health models based on deep learning in manufacturing systems and explores three directions towards the practical implementation of PHM: model interpretation, model adaptability and robustness enhancement, and cost-benefit analysis of maintenance strategies. In terms of model interpretation, the RNN-LSTM-based model prediction on bearing health estimation was analyzed, and the relationship between the model input and output was investigated. The adoption of the LRP technique improved the explainability of the LSTM model beyond predictive maintenance applications. To enhance model adaptability and robustness, a Transformer-based method was developed for fault diagnosis and novel fault detection, which achieved superior performance compared to conventional fault classification AI-based models. The decision-making aspect of PHM was addressed by conducting a cost-benefit analysis on different maintenance strategies, which provided a new perspective for decision-makers in maintenance management.</p>

Page generated in 0.1202 seconds