Tesis sobre el tema "Plastic"
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LINDSTRAND, NILS y KARL THUNELL. "From Plastic to Paper Mapping the real cost of plastics". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224931.
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Sævik, Svein. "On stresses and fatigue in flexible pipes". Norway : Dept. of Marine Structures, the University of Trondheim, 1992. http://catalog.hathitrust.org/api/volumes/oclc/27348152.html.
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Zolotaryova, A. "Plastic surgery". Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33929.
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Plastic surgery is a medical specialty concerned with the correction or restoration of form and function. Though cosmetic or aesthetic surgery is the best-known kind of plastic surgery, most plastic surgery is not cosmetic: plastic surgery includes many types of reconstructive surgery, hand surgery, microsurgery, and the treatment of burns.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33929
4
Kaartinen, Johanna. "A Checklist for Plastic Product Design: Preventing Pitfalls in a Design Process and Premature Failures of Plastic Products". Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-9683.
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Designing an injection molded plastic part requires optimizing the part with respect to various stakeholders’ needs throughout its life cycle. The conditions in which a product is operating in service are often inadequately understood or specified, resulting in wrong material selection, which in turn leads to failure when the product is used. Many aspects interrelate with the initial part design and the essential rules of each should be taken into account to ensure a well-functioning plastic product. Regardless, a part design often passes sequentially from concept development to the manufacturing phase with features that unnecessarily complicate production, add costs and weaken the intended embodiment of the product. Therefore, a checklist was developed to ensure that oversights do not happen and verify that a design fulfills the requirements set for it. The commissioning company in the project was the design office Sytyte Oy. The aim of this thesis work was to investigate the effects of design decisions on the product’s feasibility and performance in service. The study focused on the underlying reasons for failures in plastic products, failure phenomena and ways of preventing them. The project started with literature research. To support the theoretical review, a small-scale survey was conducted among operators in plastic industry in Finland to strengthen the outcome of the project. The findings from the research were compiled into a checklist. The approach into the list was adopted from the FMEA method aiming to create a stripped-down version of it. The result offers a tool for anticipating and spotting possible failures by bringing up the influences that most frequently affect the part performance. It contributes to preventing delays in processing and premature failures in service. The checklist was verified by specialist consultation to receive suggestions and requirements for improvements and to ensure its reliability.
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Mali, Sarvesh. "Study on plastic and mechanical properties of plastic stabilized returned plastic concretes containing supplementary cementitious materials". Thesis, Curtin University, 2016. http://hdl.handle.net/20.500.11937/1068.
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The growing concern for ready mix concrete industry is the disposal of returned unused concrete. In a plastic state, the concrete is a perishable product and the disposal of any unused concrete provides a set of challenges. However, little is known about the most effective parameters for recycling of returned plastic concrete without adversely affecting its properties. The present research has conducted laboratory trials to establish an optimal process for stabilizing returned plastic concretes using set-retarding admixture called “stabilizer”. Three types of cements, widely used in construction industry in Australia, are used in this research. The first is the ordinary Portland cement (OPC), while the rest are blended cements containing 25% class F fly ash and 65% slag as partial replacement of OPC.
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Doshi, Shailesh R. "A novel coextrusion process for the manufacture of short fiber-reinforced thermoplastic pipe /". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72817.
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Pitteri, Silvio. "Processing and evaluation of filled thermoplastics". Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.253309.
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Burt, Christopher. "Plastic scintillation spectrometry". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/72351/.
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Plastic scintillators provide homeland security organisations with large area, low cost gamma-ray counters at international borders. Currently these detectors connot distinguish between the sources they detect, leading to high false alarm rates during primary screening. These alarms must be followed up by time consuming secondary screening techniques using spectroscopic detectors. Here we review current PVT scintillators and present a range of techniques that optimise their characteristics. By combining these optimisations with Symetrica's spectral deconvolution and isotope identification software, PVTdetectors were given isotope identification ability. Far from being simple gamma-ray counters, these detectors were used to successfully identify a range of complex isotopes, such as Eu-152, Ra-226 and Th-232. The resulting clarity produced by these detectros was impressive, with a measured full width at half maximum of ~5% at 662keV in deconvolved Cs-137 spectrum. Detector designs are also presented here which allow PVT detectors to identify a full range of isotopes during primary screening, potentially eradicating the need for follow up examinations.
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Busillo, Eric. "Characterization of plastic hypodermic needles". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26584.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Colton, Jonathan; Committee Member: Ku, David; Committee Member: Prausnitz, Mark. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Al-Ati, Tareq. "Oxygen permeation of virgin HDPE films versus recycled HDPE films /". Online version of thesis, 1994. http://hdl.handle.net/1850/11875.
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Dura, Matthew Jonathon. "Behavior of Hybrid Wood Plastic Composite-Fiber Reinforced Polymer Structural Members for Use in Sustained Loading Applications". Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/DuraMJ2005.pdf.
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Bodalia, Raj. "An investigation of the "walking" behavior in the manufacturing of biaxially oriented polypropylene films /". Online version of thesis, 1988. http://hdl.handle.net/1850/10691.
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Aw, Cheong Soon (Samuel). "A study to evaluate the permeation characteristics of black tea flavors and linalool in four different plastic films /". Online version of thesis, 1995. http://hdl.handle.net/1850/11853.
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Ruan, Haihui. "Collision between two perfectly plastic beam structures : modeling and verification /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?MECH%202004%20RUAN.
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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 235-241). Also available in electronic version. Access restricted to campus users.
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Moran, Matthew T. "Testing the predictability of water-based flexographic inks on plastic substrates /". Online version of thesis, 1993. http://hdl.handle.net/1850/11271.
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Troop, Nicholas Mark. "Investigation of plastic package related failure mechanisms in plastic encapsulated integrated circuits". Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/10543.
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An experimental study has been conducted into the effects of package related failures in plastic encapsulated semiconductors. As a result of an extensive literature survey particular emphasis was placed on thermal and moisture related failure mechanisms. A number of accelerated life testing techniques including Highly Accelerated Stress Testing (HAST) were used to induced parameter drift and catastrophic failures. Examples of both insertion and surface mount package types were studied. Observations were made on the parameter drift and catastrophic failure mechanisms of plastic encapsulated Bipolar Junction Transistors in dual in line packages. Gain degradation was observed to be the most sensitive parameter of those measured. It is proposed that this is a result of an increase in the extended surface depletion region area due to a degradation in the surface cleanliness. A theoretical analysis of the build up these traps is presented. Package performance test chips were used to monitor the moisture resistance properties and thermal performance of Quad Flat Pack packages. Surface leakage path effects, corrosion onset and thermally induced stresses were monitored using this technique. A computer controlled measurement system was assembled for data acquisition and logging. It is believed that these techniques will be of use in the investigation into the suitability of different package plastic styles for high reliability applications such as military and aerospace systems.
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McDonald, Seonaidh. "The management of post-consumer plastics waste recycling in the UK". Thesis, University of Stirling, 1996. http://hdl.handle.net/1893/1786.
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This thesis examines the management of post-consumer plastics waste recycling in the UK. It brings together information and approaches from a number of disciplines in order to present a comprehensive view of the post-consumer plastics waste recycling industry and provide insight into participation issues. Two Scottish collection schemes are utilised as case studies throughout. The thesis summarises current practice in post-consumer plastics recycling and describes the processes associated with it. It also presents a summary of legislation relevant to plastics recycling in the UK, EC and US in particular. The thesis includes a quantitative survey of 500 members of the public that analyses their recycling behaviour and factors that affect motivation. It also looks at public perceptions of plastics. This is complemented by a qualitative study of plastics recyclers that examines recycling routines in more detail, and explores issues that affect the participation, and quality of donation, of individuals. The evaluation of post-consumer plastics recycling schemes is discussed, and models are developed in order to assessth eir financial viability. The lessons gained from this programme of research are then summarised in a policy framework.
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Toor, A. P. S. "Biaxial cyclic plastic bending". Thesis, Coventry University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372393.
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Valnes, Lars Magnus. "Accumulated Plastic Strain Program". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26981.
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In this thesis we will look at the implementation and results of the APS program. The program computes the accumulated plastic strain in a umbilical tube for the deformations axial tension, bending and internal pressure. The computation is based on solving incremental problems with the finite element method and the return-mapping algorithm. The return-mapping algorithm encountered convergence failure for large strain increments, this was solved by using the strain increment of $1.0e\sp{-4}\%$.The implementation of axial tension and bending was consistent with the results provided by Nexans Norway.While the plastic behaviour of the internal pressure proved to be more complex, so the implementation requires improvement.
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Donkin, Richard Philip. "Plastic photovoltaic roof tiles". Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/4397.
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Thesis presented in partial fulfilment of the requirements for
the degree of Master of Engineering in Renewable and
Sustainable Energy at the Stellenbosch University.Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: This project investigated the feasibility of incorporating photovoltaic cells into plastic roof tiles using injection moulding. Such tiles have the potential to provide robust and distributed electricity contained within the building envelope. Current-voltage curves of amorphous silicon modules were measured under illumination using the PVPM 2540C power measuring instrument, both before and after moulding. The efficiency after moulding was reduced by 53% to 88%, with modules that were heated for longer being degraded more. Thus the duration of exposure to high temperatures affected the extent of performance reduction during moulding. This suggested that faster moulding at a lower temperature or faster cooling could solve the problem. Economic feasibility was examined by calculating the levellised cost of electricity provided by the tiles. A large-scale development in the Western Cape was simulated using a typical meteorological year of weather data and using the anisotropic diffuse irradiance model of Perez et al. (1988). Avoided costs due to replaced roofing, avoided costs due to electricity distribution infrastructure, and Clean Development Mechanism credits were accounted for. The cost of energy calculated was R11/kWh in 2010 rands, which did not compete with the price of conventional grid-based electricity at R1.8/kWh. The importance of the cost of balance-of-system components, such as the inverter, and not only of the photovoltaic modules, was highlighted for future cost reductions. Several clear guidelines for manufacturing photovoltaic roof tiles were discovered. The most important of these was that many bypass diodes make the system more robust.
AFRIKAANSE OPSOMMING: Hierdie projek het die haalbaarheid van die integrasie van fotovoltaïse selle in plastiek dakteëls deur spuitvorming ondersoek. Sulke dakteëls het die vermoë om robuuste en verspreide elektrisiteit te lewer, sonder om die gebou se vorm te verander. Stroom-spanning kurwes van struktuurlose silikon eenhede is onder verligting gemeet met die PVPM 2540C kragmeet instrument, voor en na spuitvorming. Die doeltreffendheid na spuitvorming is met 53% tot 88% verminder, met groter vermindering in die eenhede wat langer warm was. Dus het die duur van blootstelling aan hoë temperature die mate van vermindering van doeltreffendheid beïnvloed. Dit het suggereer dat óf vinniger spuitvorming by laer temperature óf vinniger verkoeling die probleem kan oplos. Ekonomiese haalbaarheid is ondersoek deur die koste van die elektrisiteit wat deur die dakteëls gelewer is te bereken. ’n Groot behuisingsontwikkeling in die Wes-Kaap is gesimuleer deur ’n tipiese weerkundige jaar van weerdata en die anisotroop model vir verspreide ligstraling van Perez et al. (1988) te gebruik. Vermyde kostes van vervangde dakteëls, vermyde kostes van elektrisiteit distribusie infrastruktuur en krediete van die Meganisme vir Skoonontwikkeling is in ag geneem. Die elektrisiteitskoste was R11/kWh in 2010 se randwaarde, wat nie mededingend met die R1.8/kWh koste van gewone netwerk elektrisiteit was nie. Die belang van die kostes van die res van die installasieonderdele, soos die wisselrigter, en nie net die fotovoltaïse eenhede nie, is beklemtoon vir kostevermindering in die toekoms. Verskeie duidelike riglyne vir die vervaardiging van fotovoltaïse dakteëls is voorgestel. Die belangrikste van hierdie was dat meer omloopdiodes die installasie meer robuust maak.
Centre for Renewable and Sustainable Energy Studies
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Rydholm, Rosanna. "Metamorphosis - Making plastic transparent". Thesis, KTH, Arkitektur, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298812.
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In this thesis project I try to make visible the complex problems behind the plastic pollution crisis, the skewed ideas of synthetic plastic and recycling we as consumers are taught, and in what way architecture can help make these systems visible. This is achived through a design method of growth and transformation using plastic waste to create a building that uncovers what would otherwise not bee seen.
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Kasichainula, Nagesh. "Mechanic characterization of reinforced rigid polyurethane foams /". free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418038.
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Khan, Mohammad Younis. "The mechanisms of plastic flow in semi-plastic crystals under the hardness indentation". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279911.
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Kang, JiJun. "Determination of elastic-plastic and visco-plastic material properties from instrumented indentation curves". Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13509/.
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Instrumented indentation techniques at micro or nano-scales have become more popular for determining mechanical properties from small samples of material. These techniques can be used not only to obtain and to interpret the hardness of the material but also to provide information about the near surface mechanical properties and deformation behaviour of bulk solids and/or coating films. In particular, various approaches have been proposed to evaluate the elastic-plastic properties of power-law materials from the experimental loading-unloading curves. In order to obtain a unique set of elastic-plastic properties, many researchers have proposed to use more than one set of loading-unloading curves obtained from different indenter geometries. A combined Finite Element (FE) analysis and optimisation approach has been developed, using three types of indenters (namely, conical, Berkovich and Vickers), for determining the elastic-plastic material properties, using one set of ‘simulated’ target FE loading-unloading curves and one set of real-life experimental loading-unloading curves. The results obtained have demonstrated that excellent convergence can be achieved with the ‘simulated’ target FE loading-unloading curve, but less accurate results have been obtained with the real-life experimental loading-unloading curve. This combined technique has been extended to determine the elastic and visco-plastic material properties using only a single indentation ‘simulated’ loading-unloading curve based on a two-layer viscoplasticity model. A combined dimensional analysis and optimisation approach has also been developed and used to determine the elastic-plastic material properties from loading-unloading curves with single and dual indenters. The dimensional functions have been established based on a parametric study using FE analyses and the loading and linearised unloading portions of the indentation curves. It has been demonstrated that the elastic-plastic material properties cannot be uniquely determined by the test curves of a single indenter, but the unique or more accurate results can be obtained using the test curves from dual indenters. Since the characteristic loading-unloading responses of indenters can be approximated by the results of dimensional analysis, a simplified approach has been used to obtain the elastic-plastic mechanical properties from loading-unloading curves, using a similar optimisation procedure. It is assumed that the loading-unloading portions of the curves are empirically related to some of the material properties, which avoids the need for time consuming FE analysis in evaluating the load-deformation relationship in the optimisation process. This approach shows that issues of uniqueness may arise when using a single indenter and more accurate estimation of material properties with dual indenters can be obtained by reducing the bounds of the mechanical parameters. This thesis highlights the effects of using various indenter geometries with different face angles and tilted angles, which have not been covered previously. The elastic-plastic material parameters are estimated, for the first time, in a non-linear optimisation approach, fully integrated with FE analysis, using results from a single indentation curve. Furthermore, a linear and a power-law fitting scheme to obtain elastic-plastic material properties from loading-unloading indentation curves have been introduced based on dimensional analysis, since there are no mathematical formulas or functions that fit the unloading curve well. The optimisation techniques have been extended to cover time-dependent material properties based on a two-layer viscoplasticity model, has not been investigated before.
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Kazemi, Yasamin. "Mechanical and morphological characterization of wood plastic composites based on municipal plastic waste". Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29823/29823.pdf.
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Les développements récents de la législation associée aux impacts environnementaux des déchets plastiques d’origine post-consommation ont mené à des efforts sur le développement de techniques viables de recyclage. Ainsi, le but de cette recherche était de produire des composites bois-plastique (WPC : wood plastic composites) à partir de la fraction légère des déchets plastiques municipaux (post-consommation) et de résidus de transformation du bois (sciure). Afin d’améliorer la compatibilité et l’adhésion entre le polyéthylène (PE) et le polypropylène (PP), un copolymère d’éthylène-octène (EOC: ethylene-octene copolymer) a été utilisé pour développer la compatibilité entre les phases polymères tout en agissant comme modificateur d’impact. L’ajout de PE et PP maléatés (MAPE: maleated polyethylene; MAPP maleated polypropylene) a permis de fournir une meilleure compatibilité entre la matrice polymère et la farine de bois. Les effets combinés de tous les composants ont mené à la production de composites présentant des propriétés morphologiques (dispersion et adhésion) et mécaniques (traction, torsion, flexion et impact) intéressantes après l’optimisation de l’ensemble des additifs (mélanges d’agents couplants).
Dans un second temps, des composites structuraux à trois couches ont été produits à partir des matériaux composites mentionnés plus haut afin d’étudier l’effet des paramètres de design sur les performances en flexion et à l’impact. Les paramètres étudiés incluent la teneur en bois, l’épaisseur des couches individuelles de composite, ainsi que la séquence et la configuration d’empilement des différentes couches (structures symétriques et asymétriques). Enfin, la théorie classique des poutres a été utilisée avec succès pour prédire le module en flexion et ce, avec un maximum de 10% de déviation pour ces structures complexes.Recent legislations associated with environmental impacts of post-consumer plastic wastes have driven substantial attention toward developing viable recycling techniques. Therefore the aim of this research was to produce wood plastic composites (WPC) from the light fraction of municipal plastic wastes (post-consumer) and wood processing residues (sawdust). In order to improve compatibility and adhesion between polyethylene (PE) and polypropylene (PP), an ethylene-octene copolymer (EOC) was used to compatibilize the polymer phases and also to act as an impact modifier. Addition of maleated polyethylene (MAPE) and maleated polypropylene (MAPP) provided improved compatibility between the polymer matrix and the wood flour. The combined effect of all the components was found to produce composites with interesting morphological (dispersion and adhesion) and mechanical properties (tension, torsion, flexion and impact) after optimization of the additive package (blend of coupling agents). In the second phase, three-layered structural composites were produced from the aforementioned composites to investigate the effects of design parameters on their flexural and impact performance. The studied parameters include wood content, thickness of individual composite layers, as well as stacking sequence and configuration (symmetric and asymmetric structures). In addition, the classical beam theory was successfully used to predict the flexural modulus within 10% of deviation for these complex structures.
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Wadstein, Victor. "Circular Economy in Plastic Production : The recycling challenges and solutions in plastic production". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264551.
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The consequences of the linear economy of plastic production has started to show. Media reports of "plastic seas," beaches full of waste, and habitats and environments destroyed. The question on how to make plastic production more circular have been a hot topic. Every year 311 million tonnes of plastic gets produced around the world. The plastics that can be recycled are thermoplastics. 70% of all produced plastic is made from five different plastic materials, PVC, PET, EPS, PP, and HDPE. Of the total of 311 million tonnes 87 million tonnes of that plastic is plastic packages for household consumers. Of that 87 million tonnes 32% of that is never collected, ending up in the oceans. Sweden is doing well compared to most countries, 99% of all plastic in Sweden is collected. The number is much thanks to all the regulations, recycling organs, and producer requirements that are active in Sweden compared to many other countries. This report is going to point out some important challenges and its solutions to move towards a globally circular economy. Sweden still faces challenges. Of all plastic collected only 50% goes into recycling while the other 50% ends up for incineration to energy recovery, to warm up houses and give electricity to cities. There are four different methods of recycling in facilities today. Closed - loop Open - loop Chemical recycling Energy recovery through incineration Closed - loop recycling is when the recycled product ends up as the same product after the recycling process while open - loop is when something gets recycled to a plastic product with a lower value than the original product. Chemical recycling is when chemicals in the plastic are extracted and recycle these, usually for fuels. Energy recovery through incineration is when plastic waste is burnt down to recover the energy stored in the plastic. The most common recycling methods in Sweden are open-loop recycling and energy recovery through incineration. One plastic container differs from the rest. The PET - bottles. Of all plastic bottles 85% are collected and recycled in Sweden much thanks to the deposit-refund system available in Sweden. Plastic bottles often follow a process called URRC process, which is a full process from collecting plastic bottles to selling clean plastic flakes that can be renewed to new plastic bottles. Sweden is building the largest recycling facility in Europe, with a technology called "Near-echnology" which is a technology with Near-infrared light to efficiently sort out coloured and clear plastic as well as type of material and chemical compound. This technology will help the facility sort out more than 50% plastic waste compared to other facilities in Europe, an essential step toward a circular economy. Another meaningful action is in the form of global and international producer recommendations, where strict regulation regarding production, design, and materials are agreed upon that favours packaging improving its recycling abilities. These regulations come from the recycling companies such as Returpack and Plastkretsen.Konsekvenserna från en linjär ekonomi inom plastproduktion har börjat att visas. Media rapporterar om "plast hav", stränder fulla med avfall med habitat och miljöer förstörda. Frågan hur man kan göra plastproduktionen mer cirkulär har varit ett hett debatterat ämne. Varje år produceras 311 miljoner ton plast runt om i världen. Plasten som idag går att återvinna kallas Termoplaster. Av de plasterna består 70% av dessa olika plastmaterial, PVC, PET, EPS, PP och HDPE. Av all tillverkad plast är 78% miljoner ton plastförpackningar varav 32% av det som tillverkas hamnar i haven. Sverige sköter sig bättre än många andra länder när det gäller uppsamling av plast plockas 99% upp. Denna siffra är mycket tack vare de lagar, förordningar och återvinning organ som existerar i Sverige jämfört med andra länder. Detta arbete kommer att fokusera på de utmaningar som uppkommer när man ska röra sig mot en mer cirkulär ekonomi och de lösningar som finns för att klara av utmaningarna. Sverige står för ett antal utmaningar. Av all plast som samlas in i Sverige går 50% till återvinning av materialet medan 50% går till förbränning för att få ut energi, för att värma hus och generera energi till städerna. De fyra vanligaste metoderna som används i återvinning av plast idag är. Closed - loop Open - loop Kemisk återvinning Förbränning för energi Closed - loop är en återvinningsmetod som betyder att när en produkt återvinns kommer den komma ur cykeln som samma eller liknande produkt, detta kan jämföras med open - loop där produkten återvinns till ett material med sämre kvaliteter. I kemisk återvinning återvinner man kemikalierna i plasten. Vanligt är att utvinna kemikalier för att sedan använda som olika bränslen. Den sista vanligaste metoden är förbränning av plast för att få ut energin som finns lagrad i plasten. De vanligaste metoderna i Sverige är idag open - loop samt förbränning. En typ av plastförpackning skiljer sig dock mot mängden, PET - flaskor. Av alla flaskor återvinns 85% till en ny plastprodukt. Detta är mycket beroende på det välfungerande pantsystem som finns i Sverige. Insamlade plastflaskor följer i Sverige en process som heter URRC - processen. Denna process följer allt från insamling av plastflaskor till försäljning av klara plastflingor som kan återvinnas till bland annat flaskor. Sverige bygger även Europas största återvinningscentral för plastinsamling. Med en ny teknologi som de kallar "Near- Technology" som bygger på Near - infrarött ljus´ skall öka precisionen på sortering av plasten. Från material, färg och kemisk uppsättning. Potentialen är 50% mer sorterad plast än någon annan anläggning i Europa. Andra nödvändiga åtgärder för att skapa en cirkulär ekonomi är i form av strikta förordningar, skärpa lagar och att plastproducenter följer de rekommendationer som kommer från till exempel, Returpack och Plastkretsen.
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Maiani, Giorgia <1994>. "This is a plastic world. Ricerca sulle implicazioni del consumo e sull'inquinamento causato dalla plastica". Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/20698.
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La tesi, facente riferimento all'ambito di sociologia dei consumi, indaga il comportamento d'acquisto dei consumatori, le motivazioni che spingono un utente ad acquistare un oggetto e le successive implicazioni. Successivamente, viene presentato un focus sulla tematica dei rifiuti e l'interazione che i consumatori hanno con essi. Infine, si sviluppa un inquadramento sulla plastica, che attualmente presenta una delle più grandi minacce per gli esseri viventi tra tutte le tipologie di rifiuti. La tesi si pone l'obiettivo di migliorare l'interazione dei consumatori con i rifiuti.
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Polito, Carmine Paul. "The Effects Of Non-Plastic and Plastic Fines On The Liquefaction Of Sandy Soils". Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/30243.
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The presence of silt and clay particles has long been thought to affect the behavior of a sand under cyclic loading. Unfortunately, a review of studies published in the literature reveals that no clear conclusions can be drawn as to how altering fines content and plasticity actually affects the liquefaction resistance of a sand. In fact, the literature contains what appears to be contradictory evidence. There is a need to clarify the effects of fines content and plasticity on the liquefaction resistance of sandy soils, and to determine methods for accounting for these effects in engineering practice.
In order to help answer these questions, a program of research in the form of a laboratory parametric study intended to clarify the effects which varying fines content and plasticity have upon the liquefaction resistance of sandy sands was undertaken. The program of research consisted of a large number of cyclic triaxial tests performed on two sands with varying quantities of plastic and non-plastic fines. The program of research also examined the applicability of plasticity based liquefaction criteria and the effects of fines content and plasticity on pore pressure generation. Lastly, a review of how the findings of this study may affect the manner in which simplified analyses are performed in engineering practice was made.
The results of the study performed are used to clarify the effects of non-plastic fines content and resolve the majority of the inconsistencies in the literature. The effects of plastic fines content and fines plasticity are shown to be different than has been previously reported. The validity of plasticity based liquefaction criteria is established, the mechanism responsible for their validity is explained, and a new simplified criteria proposed. The effects of fines content and plasticity on pore pressure generation are discussed, and several recommendations are made for implementing the findings of this study into engineering practice.Ph. D.
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Tall, Stefan. "Recycling of mixed plastic waste". Doctoral thesis, KTH, Polymer Technology, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2928.
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Eren, Ahmet M. "An Elastic-plastic Beam Element". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607162/index.pdf.
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In this thesis, a two node nonlinear elastic-plastic beam finite element is developed to analyze large deformations. The system of equations are derived from virtual work principle, and the updated Lagrangian formulation is used. Material is assumed to be isotropic and rate insensitive obeying J2-flow rule. Work hardening characteristics of material is considered and all nonlinear terms are included. For the two node iso-parametric beam element a layered model is used to analyze through-the-thickness distribution of elastic and plastic zones. A finite element program is developed and the numerical outcomes are compared with the experimental results. A good agreement is achieved between numerical and experimental results.
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Alriksson, Kristofer. "Automotive rearview mirror in plastic". Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33042.
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The purpose of this thesis work was to carry out initial studies on Scania’s possibility to have plastic rearview mirror glasses as that for example may reduce costs and problems for Scania’s customers and enable another design of the mirror assembly. It was performed by studying the legislative and Scania demands regarding rearview mirrors to write a test program, find and order plastic mirrors, and then perform the tests and evaluate the mirrors to see if they seem good enough for Scania’s trucks. A Scania technical regulation for rearview mirror glass was also written. The tested mirrors were a Scania glass mirror as reference, a PC mirror from Sabic, a PC and a PMMA mirror from Specchidea, a mirror from SMR automotive, an ABS mirror from Ficocipa/Renault, an ABS mirror from Ford and a PC plastic from Bayer and they were tested for scratch resistance, temperature variations, impact resistance, corrosion and chemical resistance in that order. If a sample did not pass a certain test, it was not subjected to the next one. Of all samples it was only the SMR mirror and the reference glass mirror that passed the first test (scratch resistance). The others became too scratched and were not tested further. The SMR and the glass mirror also withstood all the following tests very good, the SMR mirror was the best one of the tested mirrors. Probably the SMR mirror was the best one because many of the other mirrors did not seem to have been made for outdoor conditions and because it seemed to be the most modern mirror with a good abrasion resistant coating. It was concluded that there is a future for plastic mirror glasses, that it would be interesting to do more tests on the mirrors, for example a UV test and a distortion test, and to test more mirrors as a new generation of plastic mirror glass seem to be underway. It would also be interesting to know how much cheaper and lighter the whole mirror assembly can become by changing to plastic mirror glass, which weighs 68% less than a glass mirror.
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Karlsson, Frida. "Estrogenic Substances in Plastic Bottles". Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-37117.
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We live in a time were plastic and plastic products are all around us, taking part in our everyday life. Several chemical additives can be present in plastic products, such as plastic bottles, and can have a big impact on development, as well as on the endocrine system in adults by the binding to, and disturbance of, the estrogen receptor (ER) in cells. This study has focused on a number of different plastic bottles made from different types of plastic and with variations in size and scope of use. The aim of the study was to see if any estrogenic substances leached from the bottles into water. Non-ionic water was added to the plastic bottles, and the bottles were kept at 70°C for 72 hours. The estrogenic activity in the water was determined with the U2OS-luc assay and expressed as bioassay-derived estradiol equivalents (Bio-EEQ). A difference in Bio-EEQ could be detected between the bottles and the tree plastic types used in the study. The polypropylene (PP) bottle gave the highest Bio-EEQ of 0.5 pg/ml, whereas High Density Polyethylene (HDPE) gave 0.3 pg/ml and Polyethylene Terephthalate (PET) 0.04 pg/ml. These results indicate that there is a small leakage of estrogenic substances from the plastic bottles. Further study is needed to determine whether or not the estrogenic activity in the water could have any significant biological effect in humans.Vi lever i en tid där plast och plastprodukter finns överallt runt omkring oss och har en stor del i vår vardag. Många kemiska ämnen kan återfinnas i plastprodukter, såsom plastflaskor, och kan ha en stor inverkan inte bara på den växande kroppen hos barn utan även ge endokrina störningar hos vuxna människor. Detta kan till exempel ske genom att ämnen kan binda till och påverka östrogenreceptorn (ER) i cellerna. Den här studien fokuserar på plastflaskor gjorda av olika typer av plast och med varierande storlek och användningsområde. Syftet med studien var att se huruvida några östrogena substanser kunde lakas ut i vatten som förvarades i flaskorna. Flaskorna fylldes med avjoniserat vatten och förvarades i 70°C i 72 timmar. Östrogenaktiviteten i vattnet mättes sedan i en cellbaserad testmetod, kallad U2OS-luc assay, där den samlade biologiska effekten av alla östrogena ämnen kan mätas. Effekten uttrycks som bioassay-derived estradiol equivalents (Bio-EEQ). Vatten från polypropenflaskan (PP) gav det högsta Bio-EEQ på 0,5 pg/ml medan högdensitetspolyeten (HDPE) gav 0,3 pg/ml och polyetylentereftalat (PET) ett Bio-EEQ på 0,04 pg/ml. Dessa resultat indikerar att plastflaskorna läcker ut små mängder östrogenlika ämnen. Vidare studier behöver göras för att avgöra huruvida detta läckage utgör någon risk för människor.
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Sayahi, Faez. "Plastic Shrinkage Cracking in Concrete". Licentiate thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-133.
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Early-age (up to 24 hours after casting) cracking may become problematic in any concrete structure. It can damage the aesthetics of the concrete member and decrease the durability and serviceability by facilitating the ingress of harmful material. Moreover, these cracks may expand gradually during the member’s service-life due to long-term shrinkage and/or loading. Early-age cracking is caused by two driving forces: 1) plastic shrinkage cracking which is a physical phenomenon and occurs due to rapid and excessive loss of moisture, mainly in form of evaporation, 2) chemical reactions between cement and water which causes autogenous shrinkage. In this PhD project only the former is investigated. Rapid evaporation from the surface of fresh concrete causes negative pressure in the pore system. This pressure, known as capillary pressure, pulls the solid particles together and decreases the inter-particle distances, causing the whole concrete element to shrink. If this shrinkage is hindered in any way, cracking may commence. The phenomenon occurs shortly after casting the concrete, while it is still in the plastic stage (up to around 8 hours after placement), and is mainly observed in concrete elements with high surface to volume ratio such as slabs and pavements. Many parameters may affect the probability of plastic shrinkage cracking. Among others, effect of water/cement ratio, fines, admixtures, geometry of the element, ambient conditions (i.e. temperature, relative humidity, wind velocity and solar radiation), etc. has been investigated in previous studies. In this PhD project at Luleå University of Technology (LTU), in addition to studying the influence of various parameters, effort is made to reach a better and more comprehensive understanding about the cracking governing mechanism. Evaporation, capillary pressure development and hydration rate are particularly investigated in order to define their relationship. This project started with intensive literature study which is summarized in Papers I and II. Then, the main objective was set upon which series of experiments were defined. The utilized methods, material, investigated parameters and results are presented in Papers III and IV. It has been so far observed that evaporation is not the only driving force behind the plastic shrinkage cracking. Instead a correlation between evaporation, rate of capillary pressure development and the duration of dormant period governs the phenomenon. According to the results, if rapid evaporation is accompanied by faster capillary pressure development in the pore system and slower hydration, risk of plastic shrinkage cracking increases significantly.
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Biber, Nicolas Francis Alexandre. "Plastic fragmentation in the environment". Thesis, University of Plymouth, 2016. http://hdl.handle.net/10026.1/6568.
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Microplastics are small piece of plastic debris < 5 mm in diameter, which arise and enter the environment either as a consequence of the direct release of small pieces of plastic debris or as a consequence of the fragmentation of larger items. They are widely distributed in the marine environment, on shorelines, at the sea surface, on the seabed. They are also ingested by a variety of marine organisms, and there is some evidence that this may cause adverse effects. This thesis investigates the potential sources, distribution and fate of this contaminant. Deterioration of plastics in a variety of environments was examined as a potential source of microplastics. Plastics were exposed in light and shade, in air, fresh water and sea water. Their deterioration was monitored over six hundred days. The fastest rate of deterioration, by far, was observed in air, and this was further accelerated by natural sunlight. Degradation in water was much slower and it was therefore concluded that plastic debris only fragments slowly into microplastics while they are in the water, and much faster when they are washed ashore and/or remain exposed to air, for example on a beach. A method to assess the contamination of beaches by microplastics' likely predecessors - small items of plastic debris - was therefore developed. High spatial variability, which can impede comparison between surveys undertaken by random sampling was overcome by assessing deliberately selected debris accumulations. An attempt to utilise citizen science using this rapid survey approach returned too much variability between volunteers to obtain consistent results. Nevertheless, the survey method was successfully used to identify narrow opening towards the sea, small tidal range and several weeks of high on-beach waves as predictors for high contamination. Evidence of harmful effects of microplastics on animals is primarily from laboratory studies and could be substantiated by exposure experiments \emph{in-situ}. Cockles were exposed to fluorescent plastic particles in an intertidal mudflat. After two weeks, particles were still present in the sediment. However, the test material could not be identified in the cockles with enough certainty to validate the method. The thesis concludes that fragmentation of larger items of debris on land is an important potential source of microplastics. Therefore, preventing plastics that are prone to deteriorate from entering the environment is likely the most effective way to prevent the generation of microplastics. Measuring the success of such preventive measures in the field returns highly variable results, as small plastic debris are elusive. Measuring effects in the environment demands large amounts of data, and highly specific methods are required to detect microplastics in animals. The shift of environmental plastic contamination towards small particles demands that plastic debris research adjusts to the elusiveness of these particles. Large volumes of variable data on plastics density and precise biological essays will be required.
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Ionescu, Mircea. "Electrostatic separation of plastic wastes". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ28587.pdf.
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Siu, Chi-man Benny. "Environmental management of plastic waste /". View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37117464.
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Bing, Xinyang (David). "Transvection is a plastic phenotype". Thesis, Laurentian University of Sudbury, 2013. https://zone.biblio.laurentian.ca/dspace/handle/10219/2120.
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Transvection, a chromosome pairing-dependent form of trans-based gene regulation, is widespread in the Drosophila melanogaster genome. Recent studies demonstrate that transvection is sensitive to cell environment and type in D. melanogaster, implicating transvection as a complex trait. To test this possibility, we first established that trans-interactions previously documented at the Malic enzyme (Men) locus are transvection (i.e., pairing-dependent). We then characterized the sensitivity of transvection at the Men locus to changes in the environment (temperature) and genetic background (third chromosome). Transvection varied significantly across genetic backgrounds and was significantly reduced by changes in temperature, and the two factors interacted to further modify transvection, while cis-based gene regulation remained unchanged by temperature. To determine if differences in transvection observed across genetic background and temperature are related to their effects on transcription factor expression, and possibly the presence or absence of binding sites for these transcription factors within the Men locus, we tested the relationship between Men expression and five transcription factors with binding sites near the Men transcription start sit (TSS). We found correlations between the expression of at least one transcription factor, Abd-B, and the presence of binding sites for that factor, and Men expression across changes in the environment. We also determined that changes in Abd-B expression can directly affect Men expression in cis, suggesting that cis and trans-regulation can share regulatory components in at least some cases. Together, our findings stress the importance of studying genetic interactions from a dynamic perspective by incorporating both genetic and environmental variation.
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Siu, Chi-man Benny y 蕭志敏. "Environmental management of plastic waste". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45013585.
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Li, Junhong. "Elastic - plastic interfacial crack problems". Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297517.
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Farrar, P. T. K. "Plastic injection moulding machine controllers". Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378918.
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Davenport, James Charles William. "Mixed mode elastic-plastic fracture". Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357788.
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Alcazar, Jorba Daniel. "A conjugated polymer plastic gel". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45359.
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Includes bibliographical references (p. 107-119).Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.
We present a gel route to process highly oriented conjugated polymer films and fibers. The incorporation of hexafluoroisopropanol, a strong and stable dipolar group, to the polythiophene backbone enhances the solubility and especially, the hydrogen bond forming capabilities of the polymer. This functionalization enables the polymer to build up an isotropic self-supporting network structure based on a combination of polymer-polymer chain interactions and interchain hydrogenbondings. These thermally reversible physical crosslinks incorporate plasticity in the conjugated polymer gel. The gel network can be melted and then transformed via mechanical deformation to form an anisotropic gel with the chains highly aligned along the tensile direction. The oriented gel morphology comprises a distribution of crystalline clusters in an overall swollen network. In these ordered regions, conjugated backbones are [pi]-stacked with respect to each other neighbors. The mechanically induced structural rearrangement from an isotropic to an anisotropic conjugated polymer gel occurs when transitioning from the molten state to the gel state. This study highlights the versatility of incorporating plasticity in the design of conjugated polymer materials via a gel processing technology and its potential for applications.
by Daniel Alcazar Jorba.
M.Eng.
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Pieper, Steven Donald. "CAPS--Computer-aided plastic surgery". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13093.
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Nance, Richard Wesley. "Compositional explorations of plastic sound". Thesis, De Montfort University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438864.
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Roy, Kirsty. "Spray deposition for plastic electronics". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/45287.
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Spray deposition is a promising technique for the solution processing of plastic electronic devices due to its potential for high-speed, large-scale device fabrication using low capital cost equipment. Most recent reports of spray-deposited electronic devices have used ultrasonic systems for film deposition to minimise surface roughness, but such systems suffer from low materials throughput, and are consequently ill-suited to industrial manufacturing. Gas-driven spray-heads enable higher throughput materials delivery but can result in an unacceptably rough film due to the large, broadly distributed droplet sizes that are often generated and the hard-impact nature of the deposition process. This thesis describes a new automated gas-driven spray coater for the controlled deposition of a broad variety of solution processed electronic materials. It is specifically suited to the deposition of polymer films such as poly(3-hexylthiophene) (P3HT), overcoming many of the usual disadvantages of conventional gas-driven spray coaters. Key features of the system include: a novel, high performance 3D-printed spray-head for the generation of ultrafine sprays; full three-dimensional position and velocity control of the spray head; integrated temperature control; and independent control of solution and gas flow rates. To determine the optimum solution composition for spray-deposition of P3HT films, the aggregation and gelation dynamics of various P3HT/o-xylene solutions were first investigated by static light scattering. On the basis of these measurements, we conclude that dilute solutions (with polymer concentration < 5 mg/ml) of low (< 20 kg/mol ) molecular weight polymer containing a small amount of a secondary solvent. are optimal for avoiding gelation and clogging of the spay-head. For higher weight material, heating of the solution is necessary to avoid gelation. The thesis also describes the development of an optical profiling technique for the characterisation of polymer films, which provides a fast method for quantitatively characterising the uniformity of large-area, thin polymer films. Using this technique, we were able to confirm that the spray-deposition system yields high quality, thin semiconducting polymer films, allowing for the controlled fabrication of active layers in organic photovoltaic devices from non-chlorinated solvents. The influence of solution composition and deposition variables such as gas pressure, solvent composition and substrate temperature were investigated, and optimised conditions for the deposition of high quality (device-grade) thin P3HT films were thereby identified. A maximum device efficiency of 4.0 % was achieved for the spray-deposited bulk heterojunction P3HT:fullerene films processed from xylene. The results indicate that, providing the active layer is continuous, high device efficiency may be achieved even with relatively rough films, spray-coated from non-chlorinated processing solvents.
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Ramadhani, R. K. "Plastic recycling technology in Tanzania". Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/36270.
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Tanzania, officially known as the United Republic of Tanzania, is a mid-sized country in Eastern Africa bordering the Indian Ocean. It is home to a population of about 46.1 million people. Tanzania has a tropical climate, temperature range between 10°C and 32°C.
Currently, With more than 10 bottled water companies, high supply competition in commercial cities and consumption of water bottles have significantly increased, moreover, majority of entrepreneurs in Tanzania own small shops and retail business, door to door and moving shops, the amount of plastic bags and plastic material waste have been a considerable threat toward environment protection.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/36270
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Davids, Carol-Ann. "Plastic city and other stories". Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/7967.
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Plastic City and Other Stories is a set of inter-connected short stories that capture moments in the lives of members of one family. The stories traverse more than five decades of the family's years lived in Cape Town, South Africa. While the stories are essentially about the individual, greater matters - outwardly beyond the character's experience - affect and influence the decisions, choices and, ultimately, the lives of each character. The collection is underpinned by several themes - the most pertinent being the familial bond which serves as a link between stories and enables the reader to become acquainted with the characters through several perspectives as they recur through-out the collection. There are also other, more subtle themes that fonn a connection between events happening decades apart. A, not entirely unobtrusive, narrator links these independent allegories together via inter-leading pieces, adding another dimension to the collection by virtue of her role as, not only narrator, but also as family member. Nine stories with nine inter-leading chapters make up the collection of Plastic City and Other Stories.
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Persson, Annie y Johanna Bergsten. "PlaCo : The plastic collecting robot". Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295807.
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The oceans are an essential global resource for all living organisms but especially for us humans. However, year after year we continue to neglect proper recycling of our waste, resulting in litter ending up in our oceans. The majority of said litter comes from single use plastic items. Through fragmentation and erosion, the plastic dissolves to smaller pieces, once they are no larger than 5 mm theyare classified as micro- and nanoplastics. Little is known about these small plastic particles impact on marine life and marine environment. As a step towards understanding this, the robot PlaCo was created. PlaCo stands for plastic collecting which is exactly what the robot does. With the help of three filters PlaCo gathers marine debris, such as plastic, from the water in which it operates. The filters have decreasing mesh size resulting in the microplastics being caught in the last one. Once emptied, the finds can be examined and logged for future referencing. With the help of a sensor, blockages of the filters can be monitored and if detected, notice will be given to the user through a LED. In order for PlaCo to move forward and for water to travel through the filters, the robot was provided with two DC motors. A microcontroller, Arduino Uno, was used to regulate PlaCo’s functions. The performance of two different sensors, an IR-sensorand an ultrasonic sensor, were investigated as well as the robot's water cleaning capacity. The results indicate that the latter of the two sensors would be preferable due to its high reliability. However, the robot’s water cleaning capacity could not be measured due to the chosen motors not being powerful enough. In future iterations of PlaCo, thiswould need to be rectified.Globalt sett är världens hav en viktig resurs för alla levande organismer men inte minst för människan. Trots detta fortsätter vi att, år efter år, försumma återvinningen av vårt avfall vilket resulterar i att skräp i stället hamnar i haven. Majoriteten av de sopor som hamnar där är resultatet av förbrukade engångsprodukter i plast. Genom sönderfall och erosion skapas allt mindre och mindre bitar av plast. Detta resulterar i att så kallade mikro- och nanoplaster skapas. De är mindre än 5 mm i bredd och om deras påverkan på det marina djurlivet och den marina miljön vet vi mycket lite om. För att minska kunskapsluckorna och för att få en bättre förståelse för deras påverkan har nu därför PlaCo konstruerats. Med hjälp av tre sorters filter kan PlaCo samla upp marintskräp, så som plast, i vattnet där den arbetar. Filtrens finhet varierar, där det första är mycket grovt medan det sista är fint nog att klara av att samla upp mikroplaster. När PlaCo sedan töms kan mikroplasterna undersökas och dokumenteras. När en tömning behöver göras indikeras detta för användaren med hjälp utav en LED. Roboten är försedd med en sensor som läser av hur fulla filtren är. För att driva PlaCo framåt och för att underlätta filtreringsprocessen är den också försedd med två 6 V DC-motorer. Allt detta styrs med hjälp av mikrokontrollern Arduino Uno. För att uppnå bästa tänkbara funktion hos roboten undersöktes två olika sensortyper, en IR-sensor och en ultraljudssensor. Det visade sig att ultraljudssensorn var betydligt mer pålitlig än IR-sensorn och därför valde man att använda denna. Det var även av intresse att ta reda på hur mycket vatten PlaCo kunde rena per sekund. Tyvärr skulle det visa sig att de valda motorerna inte var kraftfulla nog att driva PlaCo i vattnet. Det är därför något som behöver åtgärdas i en framtida version av PlaCo.
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Alaei, Ebrahim. "Hydrodynamic-plastic modelling of sand". Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/25046.
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This thesis focuses on proposing a novel comprehensively predictive modelling framework for granular materials which builds on the hydrodynamic procedure to satisfy the principles of thermodynamics, mass, momentum and energy conservations. In developing our physical arguments we recognise that complexity of the macroscopic mechanical response of granular media is mainly a result of kinematic degrees of freedom in granular scale. We therefore employ the original concept of two-stage irreversibility by Jiang and Liu (2009) and consider an energy sink from the mesoscopic granular entropy level to the microscopic thermal entropy level. In stark contrast from previous hydrodynamic formulations for granular materials, we establish a clear passage from the granular temperature to calibrate instead our model based on the measurable kinetic pressure.
We introduce a novel coupling between the hydrodynamic formulation and plasticity theory by directly defining the evolution equations for state variables and imposing restrictions to ensure the non-negativity of the mechanical dissipation. Within our hydrodynamic-plastic framework, we construct two constitutive model variants. The first simpler model demonstrates remarkable capability to predict comprehensive rate-independent and rate-dependent phenomena, all while relying on only five previously defined mechanical constants.
We enhanced the first model to capture particle breakage effects through integration with the breakage mechanics theory (Einav 2007). This more advanced model readily maintains all the rate-independent capabilities of the first one, and demonstrates remarkable agreement with elaborated experimental breakage data from monotonic and cyclic compression and shear tests.
This thesis provides a foundation to explore and further model granular materials, as well as materials with complex internal heterogeneous mesoscopic structure, such as weakly cemented granular rocks, silts and clays.
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Misner, Scottie y Carol Curtis. "Cutting Boards (Plastic versus Wood)". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/146435.
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1p.Revised
Which is better, wooden or plastic cutting board? Recent research has confirmed the conventional belief that plastic is safer than wood for cutting meat and poultry. This article explains the reason why plastic cutting boards are better, and gives recommendations on how to keep cutting boards safe.