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  • 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.
51

Miljöpåverkan av bioplast från skogsindustriellt avloppsvatten : En jämförande livscykelanalys av polypropen (PP) och polyhydroxyalkanoater (PHA) från Gruvöns massa- och pappersbruk / Environmental impact of bioplastic from forest industrial wastewater : A comparative life cycle assessment of polypropylene (PP) and polyhydroxyalkanoates (PHA) from Gruvöns pulp- and paper mill

Eriksson, Joakim January 2020 (has links)
I den här studien har en beräkningsmodell byggts för hur PHA skulle kunna produceras av substrat i avloppsvatten från Gruvöns bruk. Därefter har en jämförande livscykelanalys utförts där PP-sugrör inom Europa ersätts med PHA-sugrör från bruket. Målet med studien är att utvärdera och jämföra miljöpåverkan för en engångsprodukt av PHA med en engångsprodukt av PP. Syftet är att undersöka ett alternativt material till PP på grund av att fossila resurser är ändliga samt att alternativa material kommer krävas i och med europeiska kommissionens förbud mot engångsplast som träder i kraft 2022. Arbetet utförs också för att bidra med mer forskningsunderlag gällande PHA från restströmmar. Livscykelanalysen utfördes med ISO-standard: 14040 och 14044 som riktlinje för utförande. 1 ton sugrör valdes som funktionell enhet och hela produktens livscykel undersöktes med undantag för användningsfasen. PHA-produktion på bruket beräknades teoretiskt där mass- och energiflöden från modellen sedan användes för miljöbedömning. SimaPro valdes som programvara för LCA-beräkning, miljödata hämtades från databasen Ecoinvent 3 och ELCD där 10 av 18 miljöfaktorer inom metoden ReCiPe midpoint (h) undersöktes kompletterat med kumulativt energibehov (CED).   Resultaten i studien visar en minskning av miljöpåverkan med 99 % om sugrör av PP skulle ersättas med sugrör av PHA från Gruvöns bruk. Samtidigt beräknades CED öka med cirka 50 %. Analyser av resultatet visar att giftighet för ekosystem i sjöar och hav vid materialframställning för PP är de största faktorerna för PP-sugrörets påverkan, motsvarande cirka 85 % av den totala miljöpåverkan. Inkludering av fler produktionsvariationer indikerar också att det finns potential att ytterligare sänka miljöpåverkan från PHA-sugrör samt att få en lägre energianvändning än för PP-sugrör genom att ändra metod för extraktion samt temperatur i fermenteringsprocessen. Resultaten är osäkra på grund av LCA-verktygets osäkerheter, brist på miljödata samt brist på studier. Resultaten kan dock användas för att se trender och potential. Ett exempel är att ingen större skillnad ses mellan engångsprodukter av PP och PHA när enbart klimatpåverkan och energi för produktion undersöks men när hela livscykeln undersöks med fler miljöfaktorer så verkar PP ha klart högre miljöpåverkan än PHA. Slutsatsen som dras är att engångsprodukter av PHA från varma restströmmar har potential att ersätta engångsprodukter av PP på ett för miljön hållbart sätt. Det kan vara en möjlig lösning till att fortsätta producera engångsprodukter som berörs av plastförbudet samt att lätta på en del av problematiken kring utarmning av fossila resurser. Mer studier gällande möjliga användningsområden samt en småskalig pilotanläggning på Gruvöns bruk rekommenderas som vidare steg för att utforska potentialen av PHA från restströmmar. / In this study, a calculation model has been built on how PHA could be produced from forest industrial wastewater at Gruvöns pulp- and paper mill. Subsequently, a comparative life-cycle analysis has been carried out where production of PP-drinking straws in Europe is replaced with PHA-straws from the mill. The objective of the study is to assess and compare the environmental impact of a disposable PHA product with a disposable PP product. The purpose of the study is to examine an alternative material for PP due to the finite nature of fossil resources and the fact that alternative materials will be required when the plastic ban from the European Commission on disposable products comes into force 2022. An additional purpose is to provide more research data on PHA from residual streams. The lifecycle analysis was performed with ISO standard: 14040 and 14044 as a guideline and 1 ton of straw was selected as the functional unit. The entire life cycle was examined with an exception of the usage phase. PHA production at the mill was theoretically calculated and mass and energy flows from the model was then used in the environmental assessment. SimaPro was selected as the software for LCA calculation, environmental data was retrieved from the Ecoinvent 3 database and ELCD database. 10 out of 18 environmental factors within the ReCiPe midpoint (h) method were investigated complemented with cumulative energy demand (CED). The results of the study show a 99 % reduction in environmental impact if drinking straws of PP would be replaced with straws from PHA from Gruvön's mill. At the same time, CED was estimated to increase by about 50 %. Analyses of the results show that the toxicity of material production to marine and freshwater ecosystems is the most influential factor in the impact of PP straws, representing around 85 % of the total environmental impact. Expansion of the calculation model showed that there is potential to further reduce the environmental impact of PHA straws as well as the energy requirements to a level that is lower than that of PP straws by changing method of extraction and fermentation. The results are uncertain due to the uncertainties of the LCA tool, lack of environmental data and lack of studies. However, the results can be used to see trends and potential. One example is that no major difference is seen between disposable PP and PHA products when only climate impact and energy for production are examined, but when the entire life cycle is examined with more environmental factors, PP appears to have a significantly higher environmental impact than PHA. The conclusion drawn in the study is that disposable PHA products from hot residual streams have potential to replace disposable PP products in an environmentally sustainable manner. This may be a possible solution to continue producing disposable products that are affected by the plastic ban and to alleviate some of the problems surrounding depletion of fossil resources. Further studies on possible uses and a small-scale pilot plant at Gruvön's mill are recommended as further steps to explore the potential of PHA from residual streams.
52

Bioplastic material from microalgae : Extraction of starch and PHA from microalgae to create a bioplastic material

Johnsson, Nathalie, Steuer, Fredrik January 2018 (has links)
Microalgae used in sewers to capture CO2 eventually turns into waste material. Through the use oftheir biomass, the waste algae can be given a new purpose. In this study attempts to extract starch or PHA from three different algae; Calothrix Scytonemicola, Scenedesmus Almeriensis and Neochloris Oleoabundans, were made. We also attempted to create a bio-based plastic material. Both Scenedesmus Almeriensis and Neochloris Oleoabundans are starch rich microalga. By washing with acetone, cryo grinding, use of ultrasonic homogenizer and dialysis, starch was likely extracted successfully. The extracted material and the plasticiser Carboxymethyl Cellulose (CMC) was used to cast plastic film. The cast film was very thin and brittle; perhaps by using different plasticisers or additives a more usable bio-based plastic material can be created. The PHA rich algae Calothrix Scytonemicola was used to extract PHA. The algae was washed with acetone, cryo grinded and then mixed with Sodium Hypochlorite(aq) and deionised water to extract the desired PHA. Due to a shortage of algae very small amounts of material could be extracted. Therefore, the casting of a plastic film was performed with commercial PH3B, which is a type of PHA. Three attempts were conducted. The first one with only chloroform, the second one with CMC and chloroform and the last one with Sucrose Octaacetate and chloroform. The film with Sucrose Octaacetate gave the best plastic material in regards to mechanical properties. / Mikroalger som används i kloaker för att binda CO2 blir till slut restavfall. Genom att använda dess biomassa kan restalgerna få ett nytt syfte. I denna studie utfördes extraktionsförsök av stärkelse samt PHA från tre olika alger, Calothrix Scytonemicola, Scenedesmus Almeriensis och Neochloris Oleoabundans. Ytterligare försök genomfördes för att försöka framställa ett biobaserat plastmaterial. Både Scenedesmus Almeriensis och Neochloris Oleoabundans är stärkelserika mikroalger. Genom att tvätta dem med aceton, kryomalning, användning av en ultrasonic homogenizer och dialys kunde stärkelse troligtvis extraheras. Det extraherade materialet blandades med karboxymetylcellulosa (CMC) för att skapa en plastfilm. Filmen blev väldigt tunn och spröd, således behövs antingen en annat mjukningsmedel eller tillägg av additiv för att skapa ett mer användningsbart biobaserat plastmaterial. Den PHA-rika algen Calothrix Scytonemicola användes vid extraktionen av PHA. Algerna tvättades med aceton och kryomaldes innan PHA förhoppningsvis extraheras med hjälp av natriumhypoklorit(aq) och avjonat vatten. På grund av en för liten mängd tillgänglig alg extraherades endast en liten mängd material. Det var därför inte möjligt att skapa en plastfilm av vårt extrakt utan istället användes kommersiell PH3B, som är en typ av PHA. Tre försök genomfördes, en med endast kloroform, en med CMC och kloroform och den sista med sucrose octaacetate och kloroform. Den sistnämnda filmen gav det bästa plastmaterialet med avseende på de mekaniska egenskaperna.
53

The experience of being the first to breastfeed in a family : an interpretative phenomenological analysis

Darwent, Kirsty Lawrie January 2014 (has links)
The benefits of breastfeeding for mother and baby are well established; however, only 37.5% of Scottish women are currently breastfeeding at six to eight weeks with less than 1% breastfeeding exclusively for six months, as recommended by UK and international health policy. Family influence is amongst the socio-demographic factors which affect breastfeeding initiation and duration and women who were not breastfed themselves are 25% less likely to initiate breastfeeding. While there is a growing body of literature which seeks to understand breastfeeding by exploring the perspectives of breastfeeding mothers, no studies can be found describing the experience of making a different feeding choice from that of one’s family-of-origin, nor of the potential impact of this decision on relationships with them. As such, this study exploring the experience of being the first in your family to breastfeed is novel. The aim of the study was to investigate the experience and meaning of being the first person to breastfeed in a family. Consequently, areas explored included women’s experience of initiating and sustaining breastfeeding when they have no immediate family history of breastfeeding, how women make sense of their decision to breastfeed and their understanding of how their decision has affected their relationships. A methodological development in the form of an Infant Feeding Genogram was used to record relevant demographic and family information and semi-structured interviews with fourteen women obtained in-depth narratives. Interpretative phenomenological analysis (IPA) was used as an approach and to analyse the data. Following the completion of idiographic analysis, cross participant analysis was undertaken and four superordinate themes emerged: Breaching Family and Social Norms; Volitions and Imperatives; Unprepared for the Challenge; and A Sacrifice but Worth It. Within these superordinate themes, 13 themes were identified and articulated. Findings from this research were synthesised to provide an account of how women experience being the first to breastfeed in a family, make sense of their decisions and the impact this has on their relationships with their family. This provides an understanding of women’s experience in an original context, and the contextualising within the existing literature generates commonalities and highlights differences between the experience of this group of breastfeeding women and the wider cohort. The findings of this research inform recommendations for practice at both an individual and public health levels, and have implications for policy makers, health professionals and breastfeeding support organisations. It is asserted that policy makers and the health service need to acknowledge the unanticipated consequences of some current breastfeeding discourses associated with health promotion practices, and take a mother and family focussed approach to breastfeeding that acknowledges women’s embodied experience, which often includes breastfeeding difficulties. A mother and family centred approach can identify and adapt to women’s support needs in their own particular context, which may include very limited community and family support for their decision.
54

Exploring the links between urban agriculture, land use and food security in the Philippi Horticultural Area (PHA)

Donn-Arnold, Natasha January 2019 (has links)
Magister Artium - MA / Hunger is more than just a feeling, it is the lack of access to safe nutritious food, which in turn may result in anger towards government, low performance, sadness and a limited will to survive. Urban agriculture has been identified as a source of livelihood for many urban residents and could fundamentally change food insecure cities like Cape Town. The Philippi Horticultural Area (PHA) is one such place with an enormous amount of potential to assist the City of Cape Town (CCT) to overcome food insecurity challenges. The PHA is the focus of this thesis that aims to determine the impacts that housing and industrial developments in the PHA have had, and might have in the future, on food security in the Greater Cape Town Area (GCTA). The specific objectives of the study are as follows: (1) To investigate the urban agricultural distribution of the PHA; (2) to investigate agricultural facilitation, people empowerment and the use of land for agricultural purposes; (3) To determine the level of access to food for people within and around the PHA; and (4) To examine the links between the urban agricultural food sector and food production. Mixed method research was employed, hinging on the Sustainable Livelihoods Approach (SLA) as the conceptual framework. Snowball sampling was used to select 68 participants who were interviewed. One key finding of the study showed that the PHA had a significant value to the participants, many of whom called the place ‘home’. Another finding is that urban agriculture provides fresh food produce to many local residents. In-depth discussions with officials and farmers, both commercial and small-scale farmers in the PHA, revealed that the PHA is a valuable portion of farmland, and contributes significantly towards food security in and around the PHA. With the use of the SLA as the conceptual framework, the study contributes towards other livelihood outcomes dependant on urban agriculture to improve access, availability and stability of food security within the PHA. Although urban agriculture is a minimal contributor to food security in the PHA, there are other benefits enjoyed by low-income communities such as food aid given by farmers to assist low-income housing communities, educational opportunities to enhance small growers in the PHA, small-scale community garden outreach and employment.
55

Desenvolvimento de uma ferramenta computacional para a análise de fluxos metabólicos empregando carbono marcado. / Development of a computational tool for metabolic flux analysis with labeled carbon.

Oliveira, Rafael David de 11 October 2017 (has links)
A 13C-Análise de Fluxos Metabólicos (13C-MFA) tornou-se uma técnica de alta precisão para estimar fluxos metabólicos e obter informações importantes sobre o metabolismo. Este método consiste em procedimentos experimentais, técnicas de medição e em cálculos para análise de dados. Neste contexto, os grupos de pesquisa de engenharia metabólica necessitam de ferramentas computacionais precisas e adequadas aos seus objetos de estudo. No presente trabalho, foi construída uma ferramenta computacional na plataforma MATLAB que executa cálculos de 13C-MFA, com balanços de metabólitos e cumômeros. Além disso, um módulo para estimar os fluxos metabólicos e um módulo para quantificar as incertezas das estimativas também foram implementados. O programa foi validado com dados presentes na literatura e aplicado a estudos de caso. Na estimação de fluxos de Pseudomonas sp. LFM046, identificou-se que esse micro-organismo possivelmente utiliza a Via das Pentoses em conjunto com a Via Entner-Doudoroff para a biossíntese de Polihidroxialcanoato (PHA). No design ótimo de experimentos para uma rede genérica de Pseudomonas, identificou-se a glicose marcada no átomo cinco como um substrato que permitirá determinar o fluxo na Via das Pentoses com menor incerteza. / 13C-Metabolic Flux Analysis (13C-MFA) has become a high-precision technique to estimate metabolic fluxes and get insights into metabolism. This method consists of experimental procedures, measurement techniques and data analysis calculations. In this context, metabolic engineering research groups demand accurate and suitable computational tools to perform the calculations. A computational tool was implemented in MATLAB platform that performs 13C-MFA calculation, using metabolite and cumomer balances, as well as a module to estimate the fluxes and a module to quantify their uncertainty. The program was validated with some classical cases from literature. From the flux estimates of Pseudomonas sp. LFM046, it was identified that the microorganism possibly uses the Pentose Phosphate Pathway along with the Entner-Doudoroff Pathway for Polyhydroxyalkanoate (PHA) biosynthesis. From the optimal experimental design for a generic Pseudomonas network, it was possible to conclude that glucose labeled at atom five is the best option to determine the flux in the Pentose Phosphate Pathway with smaller uncertainty.
56

Modulation of pha-4/FoxA and C. elegans Foregut Development by the Novel Gene smg-8

Rosains, Jacqueline January 2012 (has links)
FoxA transcription factors are central regulators of gut development in all species. In C. elegans, pha-4/FoxA is necessary to generate cells of the foregut, or pharynx. FoxA factors need to be precisely regulated for proper development, yet we know very little about FoxA regulation. To look for potential genes that act as pha-4 regulators, the Mango lab previously conducted two screens for suppressors of the lethality associated with a partial loss of pha-4 activity. Both screens uncovered smg-8, a novel gene that is highly conserved amongst metazoans. Interestingly, the human homolog of smg-8 is amplified in some breast cancers, which also depend on FoxA1. This observation makes smg-8 a very exciting gene to investigate. The goal of my thesis is to analyze smg-8 to better understand its function and potential role as a candidate regulator of pha-4/FoxA, using C. elegans as a model system. In this thesis, I show that C. elegans smg-8 does not have a role in the Nonsense Mediated Decay pathway. I find that smg-8 modulates pha-4 protein levels during embryonic development. This work is the first direct evidence that smg-8 is a modulator of pha-4. I used biochemical and bioinformatic approaches to uncover possible partners of smg-8. These approaches identified several interesting candidates that will help place C. elegans smg-8 in a functional pathway. This work has expanded our understanding of smg-8 function and lays the foundation for further investigation of the role of this novel gene as a regulator of pha-4/FoxA in C. elegans.
57

Elaboration et caractérisation de matériaux multiphasiques à base de polylactide (PLA) et de polyhydroxyalcanoates (PHA)

Gérard, Thibaut 29 August 2013 (has links) (PDF)
L'objectif de ce travail de thèse est de fournir une étude systématique et détaillée des propriétés de mélanges de PLA et de PHA préparés à l'état fondu. En particulier, le comportement rhéologique, la miscibilité, la morphologie, les propriétés mécaniques et l'influence du vieillissement physique sur les propriétés en traction des mélanges PLA/PHBV réalisés en mélangeur interne et par extrusion bi-vis sur toute la gamme de composition ont été étudiés.La sensibilité du PHBV à la dégradation thermique a été mise en évidence, ainsi que l'importance des interfaces entre le PLA et le PHBV sur le comportement rhéologique aux basses fréquences. Les analyses de calorimétrie différentielle à balayage ont montré l'immiscibilité des deux polymères. Deux types de morphologies distinctes (nodulaire et co-continue) selon la composition de mélange ont été observées par microscopie électronique à balayage et microscopie optique en réflexion. La résistance au choc des mélanges PLA/PHBV avec et sans modifiant choc a été étudiée et les propriétés en traction de différents mélanges de PLA avec du PHBV, du Lotader GMA ou du PBAT ont été caractérisées. L'ajout d'une faible quantité de phase dispersée dans la matrice de PLA, initialement fragile, permet d'augmenter considérablement son allongement à la rupture. Cependant, les propriétés ductiles obtenues diminuent avec le temps écoulé entre la mise en forme des échantillons et leur test mécanique. Une étude de l'influence du vieillissement physique sur les propriétés des mélanges à base de PLA a donc été réalisée et un modèle qualitatif a été proposé.
58

Procedūrinė humanoidų animacija / Procedural humanoid animation

Tamulionis, Andrius 01 July 2014 (has links)
Šokis ir aerobika yra judesių programų pavyzdžiai - jos susideda iš tam tikra tvarka surikiuotų, pakartotinai naudojamų komponenčių. Norint efektyviai modeliuoti tokias programas, reikalinga formali žmogaus judesių notacija. Pasinaudoję esamomis priemonėmis (3D modeliavimo įrankiai, OGRE grafikos variklis, H-Anim) ir sukūrę savas, realizavome procedūrinių humanoido animacijų veikimo schemą. Ji leidžia sudaryti žmogaus judesių programą ir yra nesunkiai suprantama net ir tiems, kurie neturi animacijos ar trimačio modeliavimo patirties. Procedūrinės animacijos užrašomos XML formatu. Jas pavaizduoja mūsų peržiūros programa. Formatas leidžia abstrahuoti judesius į "procedūras", juos apjungti į sekas ir kaupti judesių bibliotekas. Turint pavienių judesių komponentes, procedūrinės animacijos kūrimas, pildymas ar keitimas yra žymiai paprastesnis ir lankstesnis, be to, tokia animacija yra nepriklausoma nuo humanoido modelio geometrijos. / Dance and aerobics are examples of movement programs – they consist of reusable components laid out in particular order. Efficient modeling of such programs requires the usage of some formal movement notation. With the help of existing tools and standards (3D modeling packages, OGRE graphics engine, H-Anim), as well as utilizing the ones we designed ourselves, we have implemented procedural humanoid animation schema. It allows for creating human movement programs and is easy to grasp even for those with no experience in animation or 3D modeling. Procedural animations are written in XML and visualized by our viewer software. Using our format, one can abstract movements into "procedures", combine them into sequences and store them in movement libraries. With all the individual movements at hand, creating, extending and modifying a procedural animation is much more simple and flexible. Moreover, this kind of animation is independent of model's geometry.
59

Investigative study of Biopolymer contamination in conventional recycling systems

Kuzhanthaivelu, Gauthaman January 2018 (has links)
The recycling industry which is efficiently functioning now has technical expertise, contented consumers, and resource availability and capital contributors. The potential inflow of new material into this existing system should be able to fulfill all the needs of the stakeholders involved in it. With most of the polymer wastes received from the polyethylene (PE) and polyethylene terephthalate (PET), they are available in abundant crossing the threshold quantity (Cornell, 2007) needed for the recycling process to be carried for every single polymer starting from the individual source separation till the granulation of pellets with active investment for the potential expectancy of returns in the recycling market targeting suitable consumers. Unlike other polymers like polyvinyl chloride and polypropylene (PP), biopolymers fail to fulfill the necessary criteria of being in threshold quantity to carry out the recycling process. With the very small inflow of biopolymers in the recycling industry, standalone recycling units for the same is not highly performed and appreciated. In addition to this, there are possible means and ways of the biopolymers getting infused into the conventional petrochemical polymers either through the mis-throws in manual sorting or in automated sorting. Though the studies so far don't have any substantial threatening effect over the biopolymer infusion, still it has its adversity affecting the industry by other means. The volumes of biopolymers are presently small and contamination of biopolymer in the plastic waste stream is presently not a problem. However, with increasing volumes of biopolymers, this can be a problem. Contamination could then be a future problem. This study investigates that problem and checks the truth to the claims of biopolymer infusion in the conventional post-consumer recycling systems affecting the quality of the recyclates. In order to investigate this, a biodegradable biopolymer (TPS & PHA) will be mixed into a conventional polymer (PE, PP, PET) at various percentages. The mechanical and thermal properties are then measured as a function of the percentage biopolymer. In a second part of the project, the blend of conventional plastics and bioplastic is conditioned in humidity in order to simulate what will happen to a conventional polymer that has been contaminated with a biopolymer in a humid climate.
60

Investigative study of Biopolymer contamination in conventional recycling systems

Kuzhanthaivelu, Gauthaman January 2018 (has links)
The recycling industry which is efficiently functioning now has technical expertise, contented consumers, and resource availability and capital contributors. The potential inflow of new material into this existing system should be able to fulfill all the needs of the stakeholders involved in it. With most of the polymer wastes received from the polyethylene (PE) and polyethylene terephthalate (PET), they are available in abundant crossing the threshold quantity (Cornell, 2007) needed for the recycling process to be carried for every single polymer starting from the individual source separation till the granulation of pellets with active investment for the potential expectancy of returns in the recycling market targeting suitable consumers. Unlike other polymers like polyvinyl chloride and polypropylene (PP), biopolymers fail to fulfill the necessary criteria of being in threshold quantity to carry out the recycling process. With the very small inflow of biopolymers in the recycling industry, standalone recycling units for the same is not highly performed and appreciated. In addition to this, there are possible means and ways of the biopolymers getting infused into the conventional petrochemical polymers either through the mis-throws in manual sorting or in automated sorting. Though the studies so far don't have any substantial threatening effect over the biopolymer infusion, still it has its adversity affecting the industry by other means. The volumes of biopolymers are presently small and contamination of biopolymer in the plastic waste stream is presently not a problem. However, with increasing volumes of biopolymers, this can be a problem. Contamination could then be a future problem. This study investigates that problem and checks the truth to the claims of biopolymer infusion in the conventional post-consumer recycling systems affecting the quality of the recyclates. In order to investigate this, a biodegradable biopolymer (TPS & PHA) will be mixed into a conventional polymer (PE, PP, PET) at various percentages. The mechanical and thermal properties are then measured as a function of the percentage biopolymer. In a second part of the project, the blend of conventional plastics and bioplastic is conditioned in humidity in order to simulate what will happen to a conventional polymer that has been contaminated with a biopolymer in a humid climate.

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