Dissertations / Theses on the topic 'Plaster'
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Krull, Eriksen Katrine. "Introducing Plaster : Exploring Artistic Expressions of Natural Dyed Plaster." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-14892.
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Introducing Plaster is a degree work in textile design exploring the fusion of natural dyes and plaster, and how this can be applied as a textile design material. The outcome is presented as an experimental investigation, placed in the context of surface and material design. This study derived from a growing interest in how new materials can be implemented into the field of textile design using established textile techniques and methods. Natural dye, texture and flexibility where explored through the method of hands-on-experimentation. The study moved foreword by asking the question: “What happens if?”, and the findings have been analyzed and selected for further development. The final collection consists of five pieces made entirely from plaster, showing another approach to how textile techniques and methods can be developed and adapted to fit materials from another field, for instance: Plaster.
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Beach, Elisabeth. "Plaster för framtidens cirkulära ekonomi." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-25520.
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Riksdagen (2020) har beslutat att Sveriges långsiktiga ekonomi ska styras successivt över från dagens konsumtionsekonomi mot en mer hållbar cirkulär ekonomi men ändå tyckts det enligt flera av de källor som har använts att det går alldeles för långsamt med övergången. Europeiska Kommissionen (2015) beskriver den cirkulära ekonomin som “… där värdet av produkter, material och resurser bibehålls i en ekonomi så länge som möjligt och där genereringen av avfall minimeras, som ett viktigt bidrag till EU:s ansträngningar för att utveckla en hållbar, låg koldioxid, resurseffektiv och konkurrenskraftig ekonomi”. Denna studien syftar till att studera framtida plaster utifrån en cirkulär ekonomi. Studien har tillämpat Rhetorical Structure Theory (RST) för en översiktlig men systematisk litteraturanalys med avsikt av att identifiera och kritiskt utvärdera forskning för att svara på en på förhand formulerad forskningsfråga. Granskningen föregicks därmed av en plan och inkluderar såväl kvalitativ som kvantitativ korpus forskning för att hitta, markera och räkna fall av begreppsanvändning och identifiera samband mellan begrepp, det vill säga de så kallade (s k) koherensrelationerna. En kvalitativ komparativ innehållsanalys mellan korpus har används mellan promemoria, utredningar tillsatta av regeringen och vetenskapliga artiklar. Med utgångspunkt i problembeskrivning är syftet med denna examensuppgift att utveckla kunskaper om plasters möjligheter och plats inom en framtida cirkulär ekonomi på basis av tidigare forskning. Genom en undersökning av existerande forskning är de huvudsakliga frågeställningarna för uppsatsen följande: - Vilka är framtidens plaster? - Har en bionedbrytbar plast en plats i samhället? - Hur ser framtidsutsikterna ut för biobaserade plaster och bionedbrytbara plaster? - Hur ser vårat samhälle ut i framtiden? Vi lämnade det gamla skänka och reparera samhället för ett köp och sälj samhälle och det finns ekonomiska teorier om vad som var de drivande incitamenten till det. Några av de krafter till förändringen/förändringarna var bland annat tillgången till billig arbetskraft, ny byggteknik för fabriker och lager och nya transportnät. På grund av dessa delar kunde man producera med köp och sälj teknologi och utöka mervärde. Nu idag när detta hotas börjar man prova andra produktionsformer. En cirkulär ekonomi med inslag av det gamla skänka och reparera samhället uppnås genom bland annat design där man designer för att öka livslängden för plastprodukter. På grund av den framtida plastens gränsöverskridande krävs det en kombination av nya styrmedel, beteendeförändringar och forskning för att hitta plastens plats i en cirkulär ekonomi. Resultaten bygger på analys av studiens litteraturkorpus vad beträffar information om plastens roll i en cirkulär- och bioekonomiskt samhälle där dess funktion har satts i relation till dess miljönytta och möjlighet till en plats i ett kretsloppssamhälle. Med ett ökat råoljepris och styrmedel i form av skattereduktionen och bidrag för verksamheter som vill blir mer hållbara möjliggörs en framtida cirkulär ekonomi. Genom design kan plastprodukter plockas bort från för ett mer hållbart samhälle. Syftet med rapporten har delvis kunnat beskrivas men på grund av komplexiteten av ämnet har det inte funnits några enkla svar till forskningsfrågorna då de beror på faktorer som går utanför studiens ramar.In 2020, the Swedish Parliament passed a motion to move the national economic base from a linear toward a circular economy, but the transition may be moving too slowly. The European Commission (2015) describes a circular economy as ”… where the value of products, materials and resources is maintained in the economy for as long as possible, and the generation of waste minimized, as an essential contribution to the EU's efforts to develop a sustainable, low carbon, resource efficient and competitive economy”. This thesis aims to study future plastics from a circular economy perspective. The thesis has applied Rhetorical Structure Theory (RST) to produce systematic literature analysis with the intention of identifying and critically evaluating research to answer a specific research question. The review proceeded through a plan that included both qualitative and quantitative corpus research to find, mark and count instances of the use of concepts and identify conjunctions between them, that is so called coherence conjunctions. A qualitative comparative content analysis between corpora has been used involving independent scientific articles and reports from commissioned investigations appointed by the Swedish government. Based on the problem description, the purpose of this thesis is to develop knowledge about the possibilities and place of plastics in a future circular economy using previous research. Through a study of existing research, the main questions for the thesis are the following: - Plastics of the future? - A biodegradable plastic, does it play a role in the society? - What are the prospect for biobased plastics and biodegradable plastics? - What might our future society look like? We left the old donate and repair society for a buy and sell society and there are economic theories of to what was the driving incitements to that. One of which was accessibility of cheap labour, new construction technology for factories and warehouses and a new transport network that enabled factories to produce and transport goods within effectively and increase the surplus value of production (i.e. profit). Now today when global environmental challenges threaten the sustainability and profitability of this form of consumption economy efforts have emerged to uncover new production forms. A circular economy with elements of the old donate and repair society is one of them. It demands redesigning production to increase service life for plastic products. The future of plastic is at a crossroads that requires a combination of new policy instruments and changes in behaviour and research. The result is based on an analysis of the study’s literature corpus regarding information on plastics role in a circular- and bioeconomy society where its function is put in relation to its environmental benefits and its ability for a spot in a recycling society. Together with an increase in crude oil and policy instruments in the form of tax reductions and subsidies for commercial activities who want to become more sustainable it enables a future circular economy. The aim of this thesis has been fulfilled, but the complexity of the subject has led to unanswered research questions due to factors that lie somewhat outside the scope of the study.
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Reid, Bronwyn. "Cast architectural ornament : plaster and compo." Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1214384.
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Plaster and compo are both materials used for cast architectural ornamentation. Preserving, repairing, and in-kind replacing cast architectural ornamentation is necessary to maintain the integrity of a space. Plaster and compo are visually and texturally very similar materials. Compo was invented to be a less costly substitute for plaster. Whereas the two materials are easily mistaken for one another, they are chemically quite different. The ingredients and methods used to create the two separate materials exemplify this difference. Understanding the differences is key to successfully preserving the ornaments and, thus, the spaces in which they are located. Repairing plaster with compo or compo with plaster can lead to the destruction of cast architectural ornaments. Furthermore, chemical paint removers that are safe to use on plaster can deteriorate compo. It is necessary to thoroughly understand the nature of the materials so that informed decisions can be made about their treatments. The study addresses the similarities and differences, the maintenance, deterioration, repair, and replacement of the two materials.Department of Architecture
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Song, Kyung-Min, Jonathan Mitchell, and Lynn F. Gladden. "Observing microstructural evolution during plaster hydration." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-192277.
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Calcium sulphate hemihydrate (CaSO4·0.5H2O), commonly known as plaster of Paris, is used extensively in the construction, ceramics, and medical industries. There are two varieties of plaster referred to as α and β, produced by “wet” or “dry” methods
respectively. Plaster hydrates to form crystalline gypsum (CaSO4·2H2O, dihydrate). We present a comparative in situ study of the microstructural changes that occur during the hydration of the two forms of plaster at a water-to-plaster ratio of w/p = 0.8 using NMR relaxometry and electron microscopy. In the α-plaster, pores evolve gradually to form a uniform, interconnected structure. In contrast, the β-plaster hydrates faster, leading to a less homogeneous product with micro-cracks resulting from rapid chemical shrinkage.
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Song, Kyung-Min, Jonathan Mitchell, and Lynn F. Gladden. "Observing microstructural evolution during plaster hydration." Diffusion fundamentals 10 (2009) 22, S. 1-3, 2009. https://ul.qucosa.de/id/qucosa%3A14113.
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Calcium sulphate hemihydrate (CaSO4·0.5H2O), commonly known as plaster of Paris, is used extensively in the construction, ceramics, and medical industries. There are two varieties of plaster referred to as α and β, produced by “wet” or “dry” methods
respectively. Plaster hydrates to form crystalline gypsum (CaSO4·2H2O, dihydrate). We present a comparative in situ study of the microstructural changes that occur during the hydration of the two forms of plaster at a water-to-plaster ratio of w/p = 0.8 using NMR relaxometry and electron microscopy. In the α-plaster, pores evolve gradually to form a uniform, interconnected structure. In contrast, the β-plaster hydrates faster, leading to a less homogeneous product with micro-cracks resulting from rapid chemical shrinkage.
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Alexandersson, Charlotte, and Wiveca Sundström. "Designförslag på sportflaska." Thesis, University West, Department of Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-737.
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Villaseñor, Alonso M. I. "Lowland Maya lime plaster technology : a diachronic approach." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/1446427/.
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Lime plasters are mixtures of burnt lime, aggregates and other materials that are employed in masonry architecture. Lime plasters were widely used by the ancient Maya in public monumental buildings and constitute important elements of ancient Maya material culture. This research analyses archaeological samples of lime plasters from three different lowland Maya sites: Palenque, Calakmul and Lamanai. The thesis examines how these building materials changed through time, and includes samples from ca. 400 BC to the 16th century AD. In addition to the analysis of archaeological samples, the research also reviews various sources of information, including ethnographic and ethnohistorical descriptions, for the understanding of ancient Maya lime plaster production. The results demonstrate that plasters from the three sites have different characteristics that are due to different access to raw materials and different building traditions at each of the sites. Some of the changes seem to be related to changing economic and political conditions, which is very clear in the use of clays instead of lime for the manufacture of architectural plasters during the Terminal Classic periods at Calakmul and Palenque. Other observations include the use of local meteoritic deposits in the lime mixtures of Palenque, the use of non-local volcanic materials in the late plasters from Lamanai, and the likely use of volcanic ash at Calakmul for the production of hydraulic plasters. In addition to the technological analyses of ancient plasters, the research also provides suggestions for future research and recommends those analytical methods that are most suitable for the examination of Maya lime plasters.
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Berchtold, Thomas E. "Accuracy and reliability of plaster models vs electronic models." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2010. https://www.mhsl.uab.edu/dt/2010m/berchtold.pdf.
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Napier, William John. "Kinship and politics in the art of plaster decoration." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/5898b964-6fcf-40b5-9bba-b059ffa7178a.
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This thesis explores the flowering of decorative plasterwork in late renaissance Scotland, its main focus being what influenced its development, the motivation of its leading patrons, and its role in the culture of Scotland at this time. The thesis begins by assesses why plasterwork has received much less attention in Scotland compared with other building materials, primarily stone, and whether this is as a result of Scotland’s architectural history being misunderstood in its British context. Early seventeenth-century Scotland was experiencing a building boom, its patrons increasingly benefiting from government positions, better education and foreign travel, exposing them to a wide range of influences at a time when houses and estates, (the main signals of status and rank) were being much transformed and domestically improved. This period heralded a burst of decorative plasterwork patronage throughout the country. This thesis analyses the influences which existed in late renaissance interiors in Scotland and whether a native tradition of decorative plasterwork existed in Scotland, and what influence this had on later decorative plasterwork styles. This thesis also gauges the affect that an absent court had on patronage and whether significant cycles of patronage can be interpreted by a study of seventeenth century plasterwork schemes in Scotland, and the role that decoration played in the culture of Scotland at this time. Finally, this research assesses the evolution of plaster throughout the century and why it may have developed differently from English work, and considers the changing role of decorative plasterwork in the late seventeenth century.
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Sandberg, Filiph. "Flambehandling som metod för ökad vätbarhet av polyolefina plaster." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-179602.
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Liquid, pressurized natural gas in fiberglass tanks is becoming an increasingly common source of energy for the transport sector. The complete product consists of a plastic tank enclosed in fiberglass to achieve the required strength needed. Before the fiberglass coating can be applied, the surface of the tank must first undergo a flame treatment to increase the surface energy of the plastic. In this work, an investigation is made on a previous flame treatment system that could not give the plastic the properties required for a proper attachment of the fiberglass matrix. The measures taken to improve the situation are to implement a new burner system that lives up to the criteria and to investigate the various factors that affect the flame treatment. This can be achieved through a reduced trial planning as a method for evaluating the impact of the contributing factors. The solution is to provide an open ribbon burner with air and fuel through a Venturi mixer. This enables the adjustment of the lambda value to 1.07, which is an essential condition to achieve maximum adhesion to the plastic surface. The stoichiometric ratio of the flame is of great importance to give the plastic a highly polar surface and thereby increases its wettability and adhesiveness. Other significant factors are addressed in the discussion section of the report.Flytande, trycksatt naturgas i glasfibertankar blir till en allt vanligare energikälla för transportsektorn. De färdiga bränsletankarna består av en plasttank omsluten av glasfiber för att nå upp till den hållfasthet som krävs. Innan glasfibern kan appliceras måste plastens yta genomgå en flambehandling för att öka plastens ytenergi. I detta arbete görs en utredning på ett tidigare flambehandlingssytem som inte kunde ge plasten de egenskaper som krävs för att ge glasfibermatrisen möjligheten att fästa. Åtgärderna är att implementera ett nytt brännarsystem som lever upp till kriterierna och sedan utröna de olika faktorerna som påverkar behandlingen. Detta kan åstadkommas genom en reducerad försöksplanering som metod för att utvärderade bidragande faktorernas påverkan. Lösningen är att förse en öppen bandbrännare med luft och gas genom en Venturimixer. Detta möjliggör en injustering av lambdavärded till 1.07, som är ett viktigt förhållande för att uppnå maximal vidhäftningsförmåga på plastens yta. Lågans stökiometriska förhållande är av stor betydelse för att ge plasten den polär yta som höjer dess vätbarhet och vidhäftningsförmåga. Andra betydande faktorer adresseras i rapportens diskussionsdel.
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Balksten, Kristin. "Traditional lime mortar and plaster : Reconstruction with emphasis on durability." Doctoral thesis, Chalmers Tekniska Högskola, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-220119.
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Lime mortar and plaster have been investigated with the aim to improve the knowledge on how to make them as durable as before the cement technology was developed. The background was the durability problems experienced for newly produced lime plaster on the medieval churches on the island of Gotland, Sweden. In some cases the new lime plaster façades showed severe frost damages after only one winter. Although the lime was burnt and produced according to old local traditions, the lime mortar was still mixed and worked onaccording to methods developed for lime-cement mortar. This often led to a very porous lime plaster with a lime shell in the surface and such a plaster has been shown to be sensitive to frost expansion. Field studies were combined with laboratory studies of thin section specimens. Optical microscopy and scanning electron microscopy have been important analytical methods showing the porosity and the structure of the binder and aggregate materials. The investigations have been carried out on both historic and on newly made reference mortar and plaster. The field studies were carried out mainly on Gotland, using local materials. The influence of the raw materials, i.e. lime, aggregate and blending ratio was investigated. The focus has been on the workability of the fresh mortars as well as the pore structure of the carbonated plaster. The craftsmanship, meaning mixing and application of mortar and working the plaster surface, was studied in order to clarify its final pore structure. The pore structure in a material determines many of its technical properties, such as moisture transportation, compressive strength, permeability and frost resistance. All these properties are closely connected to the durability of the mortar and plaster. The permeability of the plaster has an impact also on the durability of the covered construction materials. Behind low-permeable plasters made with hydraulic binder, examples of extensive damages of rotten wood and leached lime have been shown. The investigations have shown the importance of choosing a mortar adjusted to the building construction. They also showed the importance of choosing a blending ratio adjusted to the specific binder and sand used in order to get a mortar with a suitable pore structure and good durability. It has also shown the importance of knowing when and how to work on the plaster surface in order to obtain a homogenous material that is well receptive for lime wash and has a good frost resistance. The combination of all the investigations has led to a method for reconstructing historic mortar and plaster with good durability.
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Liu, Yifan. "Preparation and properties of oral adhesive plaster containing Periplaneta extract." Магістерська робота, Kyiv National University of Technology and Design, 2021. https://er.knutd.edu.ua/handle/123456789/19275.
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This research is devoted to the development of a new type of oral adhesive tablet that combines polymer materials and natural biological extracts (Periplaneta americana). It has good adhesion, long adhesion time and high material quality. The medicine uses the natural extract of Periplaneta americana and uses its unique membrane repair effect. The material adopts high tensile strength, strong adhesion carbomer 941 and hydroxypropyl methyl cellulose polymer materials. MTT assay was used to determine the toxicity of drug-loaded adhesion layer matrix on Hela cells. The results show that ulcer patch had good biocompatibility. Finally, the drug release behavior from the ulcer patch was studied by an amino acids analysis in the release medium using amino acid analyzer. The results show that the active components of amino acids can be effectively released from the matrix of ulcer patch, which laid a foundation for the therapeutic effect.The slow-release effect of the film provides a more efficient way to treat oral ulcers. The key production process of the product in industrial production is introduced, and the corresponding suggestions are put forward.
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Komarova, O. P., and I. Y. Korneev. "Development of a new sticky material for medical adhesive plaster." Thesis, Харківський національний медичний університет, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/19466.
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Uğurlu, Elif Böke Hasan. "Characterization of Horasan plasters from some Ottoman baths in İzmir/Elif Uğurlu;thesis advisor Hasan Böke." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/mimarirestorasyon/T000342.pdf.
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Induni, Bruce. "An investigation into the survival of medieval plaster in Dorset churches." Thesis, University of Plymouth, 2006. http://hdl.handle.net/10026.1/1122.
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It is a widely held view that most internal church decoration, including plaster, was removed as part of the unprecedented campaign of restoration undertaken by the Church of England during the second half of the nineteenth century. The thesis seeks to test this view by quantifying the extent of medieval plaster surviving in Dorset churches, and setting this survival in an appropriate historical, technical and cultural context. Literature relating to church plaster on both a national and local level has been reviewed and correlated with the results of the survey and also used to explore cultural reasons for the destruction of medieval plaster. The survey has proved that there is a substantial survival of medieval plaster in Dorset churches. To date this survival has gone severely under-recorded, even in specialist literature. Perhaps the most significant finding of the survey has been the scale on which Victorian restorers have covered historic plaster with their own, rather than stripping the old and starting again from a bare substrate. Whilst this discovery has been a major success for the project, it has simultaneously highlighted the greatest weakness of the project. Since the survey is based solely on external visual examination, it has been unable to reliably estimate how much old plaster survives below Victorian overskim, only that there is peripheral evidence of its survival. Non-destructive testing systems that might overcome this problem are investigated and the results of trials reported. Techniques for improving the objectivity of visual survey are also reviewed. Survey data is analysed to determine if the probability of plaster survival can be predicted by factors such as location, date of restoration or architects involved.
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Mullen, S. Russell. "Accuracy of performing space analysis using emodels[TM] and plaster models." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3302.
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Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains vii, 56 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 36-39).
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Petersson, Hanna, and Sofia Roslund. "Tvättemission : En undersökning av polyesterplaggs fiberutsläpp vid hushållstvättning." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-202.
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Havsmiljöer är idag den slutliga anhalten för den nedskräpning av plast som kommer ifrån avloppsvatten och allmän nedskräpning. Stora mängder plastpartiklar i olika storlekar har upptäckts i haven och även inuti djur som misstagit plasten som föda. Forskning visar att en stor del av plasten är av mikroskopisk storlek, så kallade mikroplaster. Inom denna grupp förekommer textilfibrer som likt andra plaster är svårnedbrytbara i naturen. Det har genom studier påvisats att små textila fiber rinner ut med avloppsvattnet och hamnar i haven. PET är en av de vanligaste plasterna och utifrån denna tillverkas polyesterfiber som är det i särklass mest använda materialet inom textiltillverkning. Att plastfragment från textilier skadar havsmiljön är en ny upptäckt och ämnet behöver undersökas i fler dimensioner än vad forskningen hittills gjort. Projektet syftar därför till att klargöra vilka egenskaper som påverkar mängden emission av polyesterfiber vid hushållsnära tvättning. Detta uppnås genom experimentella undersökningar av olika materialkombinationer som tvättas under lika omständigheter. Tvättvattnet analyseras och fibrerna räknas för att erhålla en jämförande studie kring polyestermaterials tendens till fällning av fibrer. Tre faktorer stod till grund för framtagning av metod: utveckling och förbättring av nuvarande metod, att efterlikna hushållstvätt samt tillförlitlighet i resultat. Detta har uppnåtts genom att laborationstvättmaskiner använts istället för kommersiella då detta ger ett vetenskapligt mer säkerställt resultat, något som har bejakats i största möjliga mån i varje steg. Alla polyestermaterial är stickade, färgade och mekaniskt bearbetade på Textilhögskolan för att garantera att samtliga material är tillverkade under samma förhållanden. Olika filtreringsmetoder har testats för att fastställa säkerhet i resultatet. Framtagning av material, tvättning, filtrering och analys var de centrala huvudmomenten för det praktiska arbetet. Analysen har gjorts manuellt där varje partikel på filtret har räknats. Resultatet visade att mikrofibergarn generellt fällde mer än filamentgarn. En högre delning vid stickning gav mer emission än en lägre och att material som slitits resulterade i mer shedding. Kombination av dessa tre faktorer; mikrofibergarn, hög delning och material som slitits gav ett resultat markant större mängd fiberemission än de tyger med endast två av dessa faktorer sammansatta. Tygerna som endast innehöll en av dessa faktorer gav betydligt lägre mängd fällning. Fleecematerial stickat i mikrofibergarn visade sig fälla mindre än en slätstickad vara med samma garntyp stickad i högre delning. Metoden som använts vid framtagning av fleecematerial är ifrågasatt, då kvalitén av dessa inte tycktes motsvara en industriellt framtagen fleecevara. Därför ställer man sig kritisk till detta resultat. De tyger som gav störst respektive minst andel emission av fibrer tvättades ytterligare för att studera inverkan av upprepad tvättning. Emissionen ökade med antal tvättar tills den så småningom avtog när fibrer slitits bort. Resultatet visar att man i största möjliga mån inte bör kombinera polyestervaror i trikå med garn 100den/144f, delning 28 som är smärglad.The marine environment today, has become the end station for plastics, waste from wastewater and general litter. Large quantities of plastic particles of different sizes have been detected in the ocean, with resulting animals ingesting this mistaking it for food. Science shows that a large part of these plastic fragments are of microscopic size, named microplastics, and within this group there are textile fibres that like other plastics are resistant and detrimental to nature. Studies have shown that when washing, the wastewater carries these small textile fibres and allows them to pass trough the purification. PET is one of the most used plastics and common in polyester fibre manufacture, by far the most used material in textile manufacturing. A new discovery, finds that the plastic fragments damage the marine environment, and the subject needs to be analysed in more detail than research has covered so far. This project aims to clarify which properties affect the amount of polyester fibre emissions when domestic washing. To investigate this, experimental tests were carried out on different material combinations washed under the same circumstances. Water from the wash was analysed and fibres were counted in order to complete a comparative study of polyester materials tend to shed. Three factors were considered for developing the method: development and improvement of existing method, aiming to resemble household wash and ensure reliability of results, all done by laboration washers instead of using commercial washing machines. Safety of results has been considerably affirmed during every step. Every polyester material was knitted, coloured and mechanically processed by the research group to guarantee that all of the materials was manufactured under same conditions. Different filter methods have been used to determine safety in results. Manufacturing of material, washing, filtering and analysis were the central focus for the practical work. The analysis came from manual count of every fibre particle. The result showed that microfiber yarn generally shed more than the filament yarn. A higher gauge gave more emission than a lower and that a worn material resulted in more shedding. The combination of these three factors; microfiber yarn, high gauge and a worn material gave markedly higher results than when tested with only two factors. The tests that only contained one of these factors gave significantly lower amount of emission. Fleece knitted in microfiber yarn had a lower level of shedding than a single jersey material in same yarn type with higher gauge. The method used for manufacturing is questioned, because the quality that should correspond an industrial produced fleece was not matched. Therefore, the result is critically inspected. The two combinations from the chosen parameters that gave the most respective and the least amount fibre emission were analysed additionally with more wash to assess their further effect. Here the emission seemed to increase with the amount of wash until it eventually subsided when more or less the fibres had worn away. Based on this result, one can finally say that these three factors should not be combined to manufacture knitted material in polyester.
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Beckman, Maja. "Silver och vismut i plaster och färger : Källor till förhöjda halter i slam?" Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-27927.
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Chemical substances are spread diffusely and uncontrollably as a result of the increased consumption of goods. REVAQ is a certification system that works to reduce the flow of hazardous substances to Swedish treatment plants and to create a sustainable nutrient recycling. According to REVAQ, the yearly accumulating rate of metals should not exceed 0.2% in soil per year. Silver and bismuth are two metals that do not fulfill this requirement. The silver concentration in sludge decreased during the last decade, however the last few years, it has leveled off. The bismuth concentration has increased significantly since 2005. The aim of this study was to explore the types of plastics and paints that could be found to contain silver respectively bismuth, and to investigate whether these can be important sources of measured concentrations of silver and bismuth in sludge. The results of the substance flow analysis which was used in this study show that bismuth is probably found in ABS plastics, polyethylene plastics and polyamide plastics. These plastics are mainly found in household items. The inflows of metals in plastic to Stockholm are estimated to be 5 kg silver and 1.2 to 5.7 tons bismuth. In paints, the numbers are 19 kg of silver and 2.5 to 3.3 tons of bismuth. The stocks of metals in plastic in Stockholm are estimated to be 25 - 50 kg silver and 5.7 to 57 ton bismuth and in paints between 98 and 195 kg silver and 12 to 33 tons bismuth. The outflow of metals in plastic to Henriksdals treatment plants are estimated to be 300 g silver and 5-25 kg bismuth and in paints 0.5 kg silver and between 62 to 82 kg bismuth. According to this study, bismuth in plastic and paint are a contributing source to the measured concentrations in sludge (4.4 - 21 % respective 54 - 73 %). Silver in plastic and paints are not a relevant source for the amount of silver in sludge in treatment plants.Kemiska ämnen sprids diffust och okontrollerat till följd av en ökad konsumtion av varor. REVAQ är ett certifieringssystem som arbetar för att minska flödet av farliga ämnen till svenska reningsverk och att skapa en hållbar återföring av växtnäring. Enligt REVAQ får inte den årliga ackumuleringshastigheten för metaller öka mer än 0,2 % i mark, vilket den gör för silver och vismut. Silverhalten i slam har de senaste årtionde minskat signifikant, men de senaste åren dock planat ut. Vismut har ökat avsevärt sedan 2005. Därför är det viktigt att identifiera källor till silver och vismut i slam. Syftet med denna studie har varit att utforska vilka typer av plaster och färger silver respektive vismut återfinns i samt att undersöka om dessa kan vara signifikanta källor till uppmätta halter av silver och vismut i slam. Resultatet av den substansflödesanalys som använts i denna studie visar att vismut används i ABS-plast, polyetenplast och troligen även i polyamidplast. Plasterna används främst i hushållsartiklar. Inflödet av plast till Stockholm beräknas innehålla 5 kg silver och 1,2 - 5,7 ton vismut och för färg 19 kg silver och 2,5 - 3,3 ton vismut. Stocken för plast i Stockholm beräknas innehålla 25 - 50 kg silver och 5,7 - 57 ton vismut och för färg 97 - 194 kg silver och 12 -33 ton vismut. Utflödet av metaller till Henriksdal reningsverk beräknas vara 300 g silver och 5- 25 kg för plast och 0,5 kg silver och 62 - 82 kg vismut för färg. Enligt denna studie är vismut i plast och färg en bidragande källa till uppmätta halter i slam (4,4 - 21 % respektive 54 - 73 % ). Silver i plast och färg är inte en bidragande källa till uppmätta mängder silver i reningsverkets slam.
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Brysbaert, Ann N. "Technology and social agency in Bronze Age Aegean and Eastern Mediterraenean painted plaster." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443389.
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Nunes, João. "Fabrico de peças metálicas utilizando moldações cerâmicas e moldações em gesso." Master's thesis, Universidade do Porto, Faculdade de Engenharia, 1999. http://hdl.handle.net/10198/1856.
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Este trabalho situa-se no campo da Fundição de Precisão, no qual foram estudados processos de fabrico de moldes de precisão para a produção de peças metálicas por fundição.
Foram abordados os processos de Moldações Cerâmicas e de Moldações em Gesso dando-se destaque a este último processo.
No processo de Moldações em Gesso testaram-se amostras comerciais, para uma melhor compreensão do processo, e foram elaboradas misturas para produzir moldações para este processo. Foi dado particular interesse à influência da consistência na densidade e resistência mecânica em verde e após ciclo térmico.
Foram ainda realizados ensaios de permeabilidade e rugosidade.
No processo de Moldações Cerâmicas foi obtida uma moldação utilizando o processo implementado no INEGI/CETECOFF.
Fez-se no final uma análise de custos aos processos envolvidos durante este trabalho. This work is placed in the field of Precision Casting in witch were studied processes of precision moulds production for production of castings.
Two processes were in study: the Ceramic Moulding process and the Plaster Moulding , been the last one the main point of interest of this work.
For the Plaster Moulding process, for better understanding of the process, were tested commercial samples and new mixtures prepared. Particular interest was given to consistency influence on density and in green and dry mechanical properties.
Permeability and roughness were also performed.
In the Ceramic Moulding process a mould was obtained by the process implemented in INEGI/CETECOFF.
The costs of these processes were also analysed
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Aghajani, Farzaneh. "Additional Thermal Expansion Of Gypsum-Bonded Investment By Rapid Heating." Thesis, The University of Sydney, 1998. http://hdl.handle.net/2123/4842.
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Rudatzki, Tina. "Untersuchungen zur Abbindeexpansion von verschiedenen Artikulationsgipsen bei unterschiedlicher Lagerung." Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-126242.
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De, Milito Jose Antonio. "Avaliação do desempenho de aglomerante a base de gesso com cimento portland de alto forno e silica ativa." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258270.
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Orientador: Gladis CamariniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo
Resumo: O gesso é um aglomerante que tem sido muito empregado em revestimento de paredes. Apresenta um bom desempenho, é econômico e de fácil aplicação, mas limitado ao uso interno devido a sua sensibilidade à água. Algumas tentativas têm sido realizadas para melhorar a sua utilização em ambientes sujeitos à umidade. Neste sentido, pesquisas avançam na tentativa de empregar diferentes adições como resinas epóxi, polímeros, cimentos, escórias, impermeabilizantes, entre outros. O objetivo desta tese foi avaliar o desempenho das misturas de gesso com cimento Portland de Alto Forno e sílica ativa nos revestimentos internos e externos sujeitos à umidade. Para isso verificaram-se as propriedades macroscópicas das misturas por meio de ensaios físicos, químicos, físico-químicos e também a avaliação microestrutural utilizando a microscopia eletrônica de varredura. As misturas foram aplicadas em revestimentos de painéis de alvenaria de blocos de concreto e observados visualmente por um período de cinco anos. Além da observação visual foi verificada a resistência de aderência das misturas aplicadas internamente e externamente. Dos resultados obtidos observou-se uma possível coexistência entre o gesso e o cimento e que a adição de sílica ativa na mistura reduz a formação de etringita, principalmente nos revestimentos externos, sujeitos à umidade. A adição de cimento Portland melhora na abrasão e perda de massa, mesmo em idades mais avançadas. Assim, devido ao elevado custo de algumas adições, e as dificuldades de trabalhar com outros tipos de adição na obra, a adição de cimento Portland e sílica ativa ao gesso permitem uma melhoria de resistência, obtendo um revestimento de baixo custo e de fácil manuseio.
Abstract
Abstract: Plaster of Paris is a binding material being used in masonry as a plaster finish coat. Despite being economical, having good performance as and ease with wich it is applied in building, its use is limited to indoors. Some attempts has been made to improve its performance in external environment. In that sense, researches advance in the attempt at using several admixtures like epoxy resins, polymers, cements slags, waterproofing materials among other things. The objective of this thesis is to assess the performance of certain mixtures of rendering material containing plaster of Paris, slag cement and condensed silica fume when applied in the internal and external plaster finish coat. The macroscopic properties of the mixtures were analyzed through physical and chemical tests and also in SEM. Mixtures were applied on coatings of brick and mortar and visually inspected within five years. Bond strengths of the mixtures were measured, both in internal and external walls. Results showed compatibility between plaster of Paris and slag cement and that presence of condensed silica fume in the mixture reduced the formation of etringite, especially in the external coatings. The addition of Portland blastfurnace slag cement reduced the abrasion and the loss of mass, even in older ages. Therefore, due to the high cost of some admixtures, and the difficulty in working with other kinds of admixtures in the construction sites, the mentioned additions to the plaster rendering allow a mechanical strength improvement, thus resulting in low cost and good workability of the plaster finish coat.
Doutorado
Edificações
Doutor em Engenharia Civil
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Trovão, Ana Paula Milagres. "Pasta de gesso com incorporação de resíduo de gesso e aditivo retardador de pega." Universidade Federal do Espírito Santo, 2012. http://repositorio.ufes.br/handle/10/6171.
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Previous issue date: 2012-08-10The use of plaster in civil construction generates a large amount of waste, but it is a material that posses properties that makes it a highly competitive product. The main cause of the generation of this waste is the rapid hardening of the pastes. The incorporation of waste gypsum into the gypsum pastes results in an acceleration of the hardening process, which might increase the volume of residues generated. This dissertation aimed to develop procedure to incorporate the gypsum residue into plaster pastes without compromising the paste mechanical properties and, especially without accelerating its hardening process. Tests have been developed to evaluate the plaster pastes setting time, consistency, workability and temperature reading in the plaster pastes in the fresh state and evaluate the hardness and axial compressive strength in the hardened state. Tests results showed the viability of the incorporation of 5% gypsum waste in substitution of gypsum in the plaster paste when combined with borax retardant additive, which promoted extension of the workable time of the paste and an increase in the pastes mechanical properties
A utilização do gesso pela construção civil gera um grande volume de resíduos, no entanto é um material que apresenta propriedades que o torna altamente competitivo no mercado. A principal causa da geração desse resíduo é o rápido endurecimento das pastas. A incorporação de resíduo de gesso às pastas provoca a aceleração no processo de endurecimento, podendo aumentar ainda mais o volume de resíduos gerados. Essa dissertação teve como objetivo buscar a forma de incorporação do resíduo às pastas de gesso para revestimento de parede, sem comprometer suas propriedades mecânicas e principalmente não acelerar seu endurecimento. Foram realizados os ensaios de tempo de pega, consistência, consistência útil e leitura de temperatura nas pastas em seu estado fresco além dos ensaios de dureza e compressão axial destas no estado endurecido. Os ensaios apontaram a viabilidade da incorporação de 5% de resíduo de gesso em substituição do gesso quando associado ao aditivo retardador bórax, que promoveu ampliação do tempo de utilização da pasta e o aumento nas propriedades mecânicas ensaiadas
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Alma, Sandqvist. "Byggbranschen måste också plastbanta : En fallstudie om plaster i dagens byggande och dess hälso- och miljöpåverkan." Thesis, Luleå tekniska universitet, Industriellt och hållbart byggande, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-73215.
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Syftet med examensarbetet är att bidra med ökad kunskap om hur plastanvändningen ser ut i dagens byggande och vad den har för miljö- och hälsomässiga konsekvenser. Målet med studien är även att kunna visa på hur plastanvändningen kan förändras på ett hållbart sätt. Föratt kunna uppnå examensarbetets syfte och mål har tre stycken frågeställningar formulerats. Hur mycket och vilken typ av plast förekommer i en nybyggd villa idag? Vilka miljö- och hälsomässiga konsekvenser medför den plast som används i dagens byggande? Vad finns det för alternativa material, produkter och metoder? För att svara på dessa frågor har en grundläggande litteraturstudie gjorts kompletterat men enkvantitativ fallstudie. Fallstudien utgår från en villa som är typisk för hur nybyggda villor byggsidag, år 2018. Objektet som valts för fallstudien är en nyproducerad enplansvilla på 170kvadratmeter boyta. Plastprodukter har inventerats i stommaterial, installationer, emballageoch förpackningar. Resultatet av inventeringen visar på att 3181 kg plastprodukter inventerats i villan vilket betyder att nästan 19 kilogram plast går åt för varje kvadratmeter boyta. Viktmässigt återfanns85 procent av plasten i stommaterial, 11 procent i installationer och 4 procent till emballageoch förpackningar. Sammanställningen visar även att en övervägande del av plasten utgörs avpolystyren (PS). Därefter är polyvinylklorid (PVC), polyeten (PE) och polypropen (PP) de mestf örekommande plasterna. Plasterna har även bedömts ur ett miljö- och hälsoperspektiv. Bedömningen utgår ifrån trekategorier; toxicitet, klimatpåverkan och avfall. Resultatet av miljö- och hälsobedömningenvisar att polyeten (PE) och polypropen (PP) är de mest skonsamma plasterna för miljö ochhälsa, bortsett från biobaserade plaster. Den farligaste plasten är enligt denna studiepolyuretan (PUR) tätt följt av polyvinylklorid (PVC), polykarbonat (PC) och polystyren (PS). Miljö- och hälsobedömningen av olika plasttyper visar på att det är viktigt att plast inte ses somett material utan en grupp av många olika material med olika egenskaper som är mer ellermindre problematiska för hälsa och miljö. Analysen visar även att flera plastprodukter i byggnadens stomme kan ersättas med alternativa material och på så sätt reducera inte baramängden plast utan även de miljö- och hälsokonsekvenser som plasten medför. För installationsplast är det bästa alternativet i dagsläget att byta PVC-plast till bättre plast såsom PE och PP. Detta för att minska påverkan på miljö och hälsa både vid tillverkning ochåtervinning. För emballage- och förpackningsplast gäller det främst att minska engångsanvändningen och öka återanvändningen av förpackningsplasten. För vidare studier kan det undersökas med vilka medel kan man hjälpa beslutsfattare inombyggbranschen att välja mer hållbara material, och studera hur stor påverkan den ekonomiskaaspekten har när material ska väljas. Ett annat förslag är att titta på hur plastanvändningenskiljer sig åt för olika typer av byggnader; flerbostadshus, offentliga byggnader, fritidshus.
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Andrews, Curtis Kyo-shin. "Validity and Reliability of Peer Assessment Rating Index Scores of Digital and Plaster Models." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1208136018.
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Wiles, Joanne. "An analysis of plaster sequences from the neolithic site of Catalhoyuk (turkey) by microspectroscopic techniques." Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501333.
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An integrated analytical methodology, including spectroscopic techniques and micromorphology, has been used to analyse mud plaster sequences and natural sediments from the Neolithic site of Catalhoyuk in Turkey in order to explore the uses and perceptions of soils and space at the site. The sediments were analysed using bulk FT-IR spectroscopy, FT-IR microscopy, X-ray diffraction, Scanning Electron Microscopy with Energy Dispersive X-ray Analysis, Atomic Absorption and X-ray fluorescence spectroscopy. Mapping of multiple plaster sequences was conducted using FT-IR microscopy and spatially resolved X-ray diffraction using the synchrotron source at the Daresbury Laboratory. Experiments using the FT-IR microscope in reflectance mode and SEM/EDX were conducted directly upon the surface of thin sections so that the spectroscopic analysis could be directly combined with micromorphological analysis, retaining additional contextual information.
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Plaster, Thomas [Verfasser]. "Management und Führung im Gesundheitswesen : Ein Arbeitsbuch für Ärzte und Angehörige der Gesundheitsberufe / Thomas Plaster." München : GRIN Verlag, 2010. http://d-nb.info/1186787686/34.
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Caner, Evin. "Archaeometrical Investigation Of Some Seljuk Plasters." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1218858/index.pdf.
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The aim of the study was to investigate Seljuk Plasters used in some of their
royal administrative or residential buildings from a viewpoint of their raw
materials and technological characteristics. Some Byzantine Plasters of the
same period were also investigated to make comparison. Plasters from some
historic structures in the archaeological sites namelyAlanya Castle, Kubadabad Palaces, Syedra Archaeological Site, Aspendos Amphitheatre, Selinus Archaeological Site-Sekerhane Kö
sk and Hasbahç
e were examined. In a series of examination basic physical properties of the plasters as bulk density, porosity, water absorption capacity and water vapour permeability were obtained. The results indicated that plasters are low dense and high porous materials and having good breathing property. Mechanical properties of the plasters were expressed by the modulus of elasticity (Emod) values which were obtained from ultrasonic pulse velocity measurements. The Emod of the plasters being in the range of 1.0 to 5.6 Gpa show that they have enough mechanical strength comparable to historic mortars and bricks. Raw material composition and mineralogical properties of plasters were determined by combined interpretation of several types of analyses such as chemical analyses, particle size distribution of aggregates, petrographic analyses of thin sections by optical microscopy, scanning electron microscopic analyses of cross sections coupled with EDX for image analyses and semiquantitative elemental analyses, X-ray powder diffraction analyses for the determination of mineral phases, thermogravimetric analyses and FTIR analyses. Binder used in all plasters was found to be lime with amount in the range of 53.8-96.8% as CaCO3. The main minerals of aggregates are quartz, calcite (limestone), dolomite and opal-A. Regarding particle size distribution of aggregates it was possible to classify them into fine, coarse and mixed aggregates having rather high pozzolanicity. Study on decorative and red zigzag patterned plasters indicated presence of haematite as the source of red pigment. Study on green colored plaster also indicated presence of iron containing mineral with lower oxidation state. The Seljuk and Byzantine Masonries chosen are still surviving buildings that their plasters should be of good quality. In fact, this study approved their quality which may be due to the presence of opal-A and dolomite.
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Ribeiro, Abrahão Severo. "Produção de gesso reciclado a partir de resíduos oriundos da construção civil." Universidade Federal da Paraíba, 2006. http://tede.biblioteca.ufpb.br:8080/handle/tede/5554.
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Previous issue date: 2006-03-24Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Comparing to others binders, as Portland cement and lime, plaster is much more energetic efficient because it can be obtained at relatively low temperatures (less than 160oC). During its making process, it emits water vapor to atmosphere, instead CO2 produced by the others binders named above. Although, being a calcium sulfate that has some water solubility, irregular deposition of its residues can contaminate ground and natural source of water The resolution 307/02 of Brazilian National Environmental Council considers plaster as class C material, so, a material that generates residues for those technologies or feasible applications were not still developed to permit a recycling. Then, it is necessary to change this reality and to find a way to minimize plasters residues to environment. In this work, a possibility to obtain plaster from residues of four of its applications in civil construction (coating, sealing plates, decoration pieces, ceramic moulds) was investigated. Initially, the plaster residues volume generated at Recife Metropolitan Area was researched. After, physical, chemical and mechanical properties were obtained. X ray difractometry showed much alike between the recycled plasters and natural plaster. The same occurred with mechanical strength. Despite some small differences on others properties (as lower initial and final set time) results indicate that it is possible to recycle plaster residues. For this it is necessary to separate it of others construction materials residues in the construction site
Comparado com outros ligantes como cimento Portland e mesmo cal, o gesso apresenta muito maior eficiência energética, visto que pode ser obtido em temperaturas inferiores a 160°C. No seu processamento, ele lança na atmosfera vapor d´água, contrariamente aos dois primeiros produtos citados que emitem CO2 no seu processo de fabricação. No entanto, sendo um sulfato de cálcio que apresenta certa solubilidade em água, a deposição irregular de seus resíduos pode contaminar solos e águas. A resolução 307/02 do Conselho Nacional do Meio Ambiente considera o gesso como material classe C, ou seja, aquele que gera resíduos para os quais não foram desenvolvidas tecnologias ou aplicações economicamente viáveis que permitam uma reciclagem. Urge então reverter essa situação e encontrar formas de se minimizar a dispersão dos resíduos de gesso no meio ambiente. Uma delas é justamente promover o reaproveitamento desses resíduos. Neste trabalho foi estudada a possibilidade de obtenção do gesso a partir de resíduos de quatro de suas aplicações na construção civil: revestimento de alvenarias, placas de forro, peças de decoração, moldes para cerâmica. Inicialmente foi quantificado o volume de resíduos de gesso gerados na Região Metropolitana do Recife. Em seguida foram coletados os quatro citados tipos de resíduos. Estes materiais foram beneficiados em Laboratório e recalcinados. Em seguida foram feitos os ensaios de caracterização de suas propriedades químicas, físicas e mecânicas. Os resultados de difractometria de raios X mostraram muita semelhança entre os resíduos de gesso e a gipsita. O mesmo ocorre com as resistências mecânicas. Apesar de algumas diferenças em outras propriedades (como tempos de inicio e fim de pega) os resultados deste trabalho apontam para a possibilidade de se obter gesso a partir dos resíduos gerados na indústria da construção civil,xviii devendo-se ter o cuidado de separar nas obras esse material de contaminações com outros resíduos de construção.
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Sharek, Elizabeth. "The unsettled object." Click here to access this resource online, 2007. http://hdl.handle.net/10292/421.
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The Unsettled Object is an installational art project that considers the instability of objects in regards to their assembly, classification, and presentation, underpinned by the context of the museum and supported by Michel Foucault’s notion of the classificatory grids he discusses in The Order of Things: an archaeology of the Human Sciences. (Foucault,1970) The artefacts are being fabricated as a response to the corporeal body-on-display; its surfaces, spaces and volumes. An underlying notion of temporality and mutability is indicated in the processes of making, the objects, material responsiveness and the devices employed in the presentation of the work.
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Svensson, Sellin Viveca. "Kemikalier i livsmedelsförpackningar och dess påverkan på människors hälsa : En studie om migrering av kemikalier från produkter och livsmedelsförpackningar till livsmedel." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-73065.
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The purpose of this study was to investigate the migration of chemicals from products and food containers into food and determine the health issues of those chemicals. The study was made to help make a risk assessment of the chemicals that migrate from the products and food containers. The study was done by researching the internet and books and having interviews with suppliers, producers and resellers of the containers by e-mail or over the phone. The different materials in the food packages and products that were researched had different chemicals that were added to give the material a certain property such as colour, density and flame resistance. The result shows that a lot of our products and food containers contain a variety of chemicals. Some of the chemicals proved to be in direct correlation with the health issues of our hormone- and reproductive systems and others had a direct effect on our bigger organs. The plastic food containers and products proved to have the most additives and health issues from the added chemicals compared to the other materials. The risk assessment that was made ranged from 1 to 4 in which 1 is an indication that the material and/or chemical is toxic, a 2 indicates that it is not sure whether or not the material and/or chemical is toxic, a 3 indicates that the material and/or chemical is not toxic and a 4 indicates that more studies have to be done to be sure of the materials and/or chemicals toxicity.
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ARRUDA, Gerlânia Brasiliana de. "Rotas geoquímicas da contaminação sulfática em meios aquosos no município de Araripina/PE." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17895.
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Propriedades físico-químicas de águas superficiais represadas (profundidade: 30 cm) da região de Araripina, envolvendo pH, condutividade, OD, STD, temperatura, sulfatos, cloretos e bicarbonatos, são apresentadas neste trabalho. Este estudo foi motivado por pesquisas médicas que indicaram a poeira de gesso como responsável por 38% das internações hospitalares locais. A amostragem, no final da estação chuvosa, pressupõe um máximo de lixiviação da poeira de gesso sedimentada em solos e vegetação. A partir de focos produtores, os resultados permitiram configurar halos hidroquímicos de contaminação originados pela lixiviação da poeira de gesso e por efluentes da produção de placas de gesso. Posteriormente esses dados foram comparados com amostragem com período de estiagem. Estes halos envolvem centenas de metros de extensão, com período de estiagem orientado predominante dos ventos, determinando áreas de influência onde águas represadas e de subsuperfície estão contaminadas em SO4— (>250 mg/L até 1930 mg/L) e em cloretos (>250 mg/L até 5390 mg/L). Esta associação hidroquímica é atribuída à lixiviação de particulados de gesso e à provável presença de halita residual neste produto. A drenagem a jusante de Araripina revela contaminações por efluentes da produção de placas de gesso no domínio urbano, com contribuição adicional de efluentes domésticos sódicos e/ou clorados. No interior dos halos de dispersão de poeira/efluentes de gesso, águas represadas com concentrações elevadas em cloretos (> 200 mg/L) e sulfatos (> 250 mg/L), estão inviáveis para consumo humano. Elevadas taxas de dissolução e de residência de sulfatos e cloretos, nestes meios líquidos, mostraram aumento de concentração sulfatos e cloretos nos corpos d'água estudados principalmente no quadro de estiagem prolongada.
Physicochemical properties of dammed surface water (depth: 30 cm) of Araripina region, involving pH, conductivity, DO, TDS, temperature, sulfates, chlorides and bicarbonates, are presented in this paper. This study was motivated by medical research that indicated the dust plaster responsible for 38% of local hospitalizations. Sampling at the end of the rainy season, it assumes a maximum of dust leaching gypsum sediment in soils and vegetation. From producers outbreaks, the results helped set hydro chemical halos of contamination arising from the leaching of plaster dust and waste from the production of plasterboard. Subsequently these data were compared with a sample with the dry season. These halos involve hundreds of meters long, with prevailing dry season winds oriented, determining areas of influence where backwaters and subsurface are contaminated in SO4- (> 250 mg / L to 1930 mg / L) and chlorides (> 250 mg / L to 5390 mg / L). Hydrochemistry This association is attributed to leaching of gypsum particles and the probable presence of residual halite this product. Draining the Araripina downstream reveals contamination by waste from the production of plasterboard in the urban area, with additional contribution of sodium and / or chlorinated domestic sewage. Inside the dispersion halos of dust / waste gypsum, water dammed chlorides in high concentrations (> 200 mg / l) and sulphate (> 250 mg / L), are unfeasible for human consumption. High dissolution rates and residence of sulphates and chlorides, these liquid media showed increased concentration sulfates and chlorides in water bodies studied mainly in prolonged drought frame.
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Meyers, Julia Isabell. "Prehistoric Wall Decoration in the American Southwest: A Behavioral Approach." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194060.
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Major social and demographic changes occurred during the Pueblo IV Period (AD 1300-1600) in the American Southwest. Small scattered communities aggregated into large settlement centers with more complex social organization during this period. Mural paintings created at this time are dramatically different stylistically from murals created before the social and demographic shift. At Homol'ovi in northeastern Arizona, these mural changes were accompanied by changes in plastering behaviors, including the development of distinct pigment use patterns.The hypothesis of the present study is that the visual performance characteristics of Hopi wall decorations, such as pigment sources, wall plaster colors and mural painting motifs, were part of a complex communicative system that changed as social power relationships changed and new rituals were established to support and legitimize the new social organization.Using inexpensive optical plaster and mural analysis techniques and XRF analysis of pigment samples from the ancestral Hopi sites of Homol'ovi I, Homol'ovi II and Chevelon, this research demonstrates the significance of wall decorations as social and political indicators marking transitions that occurred during the Pueblo IV and contact periods.
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Morse, Evan. "Objectified : a sculptural study /." Norton, Mass. : Wheaton College, 2009. http://hdl.handle.net/10090/8397.
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Gráf, Radomír. "Návrh technologie výroby plastového programového kotouče." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230863.
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This thesis is concerned with the appropriate design of manufacturing technology for plastic program disc including the design of plastic printing technology. At the beginning of this thesis was made an analysis of requirements for manufactured device including selection of the most appropriate technology for its manufacturing – plastic injection. In the theoretical part are described all skills needed for designing and construction of the injection mould. Partial theoretical parts are concerned with the issue of plastic materials, tools and engines for injection, and of plastic printing technology. Practical part is concerned with description of design of each single system inside the injection mould including calculation. On the basis of these calculations was selected the appropriate injection engine. The end of the practical part is concerned with the selection of the appropriate engine for printing on the plastic device which is manufactured by the technology of plastic injection. For construction of the injection mould were applied normalities of the Hasco Company and the 3D CAD system Solidworks. The conclusion of this thesis achieves the technical- economical evaluation for manufacturing of designed plastic device.
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Smith, D. Charles. "The impact of the Deir ʻAlla plaster text on the biblical interpretation of Balaam and his oracles." Theological Research Exchange Network (TREN), 1999. http://www.tren.com.
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Calisesi, Matteo. "Aerogel Incorporated Plasters and Mortars: the case study of precast panels." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13043/.
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The aim of many current studies regarding building envelopes is the improvement of their thermal resistance. In particular, many attempts have been taken to develop highly insulating materials for advanced building envelopes. The present research investigates the possibility to include aerogels in plaster and mortar products. Several samples of Aerogel Incorporated Plaster and Aerogel Incorporated Mortar were prepared by adding granules of aerogel to different types of plasters and mortars. The thermal conductivity of each sample was then measured by means of a heat flow meter apparatus. In the case of the samples of Aerogel Incorporated Mortar, the mechanical strength and the permeability were tested as well. The results showed that the thermal conductivity and the mechanical strength linearly decreased by increasing the quantity of aerogel added to the mixes. For example, while the control mixture of mortar had a thermal conductivity of 0.28 W/mK and a compressive strength of 50.3 MPa, the mixture of mortar with an addition of 36 vol.% of aerogel halved the thermal conductivity to 0.14 W/mK and reduced the compressive strength to 4.1 MPa.
Finally, an Aerogel Incorporated Mortar precast panel was designed and the hygrothermal analysis of the panel was carried out by using WUFI Pro software. Results showed that the thermal transmittance of the panel was reduced by 25% compared to traditional precast panels, which suggested that energy savings and reduced costs during the lifetime of the building could be achieved.
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Rajchot, Václav. "Vývoj tepelně izolačních a sanačních omítek pro památkovou péči." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225894.
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This thesis addressed the development renders the optimal ratio of thermal insulation and mechanical properties. In developing these materials were used alternative latent hydraulic binders. Research was conducted plasters and renders the requirements of technical standards in the Czech Republic. Work dealt with the general composition of plaster, including the use of secondary raw materials in dry plaster mixtures and thermal insulation properties and remediation plaster. Furthermore, the measured values of physical and mechanical properties of the test formulations. The best recipes were compared with plaster on the Czech market.
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Ciftci, Burcu Devrim. "Archaeometrical Studies On Plasters Of Some Historical Buildings." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608261/index.pdf.
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The present study aims to investigate the composition of historical plasters to get information about their material characteristics and their technology. Plaster samples were obtained from four Ankara Citadel houses built in late Ottoman period.
In order to determine the raw material characteristics and mineralogical properties of plasterschemical analyses, optical observation of cross sections, petrographic analyses of thin sections, elemental analyses by ICP-OES, X-ray powder diffraction analyses for the determination of mineral phases, thermogravimetric analyses and FTIR analyses were carried out. Interpretation of all the analytical examination was used to understand the composition and unique character of plaster samples studied. Observation of thin sections revealed more plaster layers than those observed in cross sections. Up to twelve layers could be observed with different colours, such as blue, red, yellow, green, white and brown. Generally, thicknesses of white plaster layers were found to be thicker than the others. In two samples, two black boundaries between plaster layers were identified which could be an indication of the use of asphalt for isolation purposes, like dampness proofing or heat insulation. Soluble salt contents of the plaster samples were in the range 3.04%-9.22%, with an average being 6.62%. The anions identified were Cl-, SO42-. In few samples, PO43-, NO2- and NO3- were found. Binder was found to be lime and gypsum. The amount of binder in terms of total calcium oxide, CaO, was found to be in the range of 33.5-43.6%, with an average being 37.9%. Amount of aggregate was about 62.1% as average. The main minerals identified in plaster samples were calcite and gypsum. Gypsum might be added to increase the strength of the plaster. Beside calcite and gypsum, quartz and pozzolanic activity related mineral, Opal-A, were found in some of the samples. In red plaster layers hematite mineral was also identified. Other colour effective elements were found to be Fe, Sb, Mn, Cu, Cr and Ni. Presence of organic additives was observed but clear identification was not established.
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Renso, Michele <1993>. "Analysis of the effectiveness of inhibitors of crystallization of soluble salts and consolidation of plaster in marine environment." Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/21370.
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Salt crystallization is a serious problem for the conservation of porous materials, in particular for those materials already damaged by the exposure to rising damp and pollutants activity, or for materials in marine environment. The high crystallization pressure can be very harmful for the integrity of the porous material itself, leading to severe damages. Starting from this issue, this thesis studied the effectiveness of different salt crystallization inhibitors and the performance of some consolidants applied on materials without any preliminary treatments for the salts removal. The first part of the work studied the "in vitro" effects of NaCl- solution with different consolidant products and different inhibitors, in order to have a preliminary observation on the influence of the salt in the systems. The second part is focused on the direct application of consolidants and inhibitors on plaster samples treated with NaCl-saturated solution. The final aim of the thesis is to evaluate the applicability of consolidants on salted plaster and to check the final effectiveness of these products in such an environment.
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Cavalcanti, Leonardo Barbosa. "Determinação de condições operacionais adequadas na desidratação do minério de gipsita para obtenção de um gesso beta reciclável." Universidade Católica de Pernambuco, 2006. http://www.unicap.br/tede//tde_busca/arquivo.php?codArquivo=25.
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Foram determinadas condições operacionais de temperatura e pressão sob as quais ocorre desidratação térmica do minério de gipsita que dá origem a um tipo de gesso beta reciclável. Com a resolução do CONAMA n 307, de 05 de julho de 2002, o resíduo de gesso proveniente da construção civil tornou-se um rejeito de difícil descarte, uma vez que esse material é considerado como contaminante para os demais componentes de um entulho e consideram que ainda não foi desenvolvida tecnologia para sua reciclagem. Neste trabalho foi elaborado e confeccionado um reator batelada em escala de laboratório para produção de gesso beta a partir do minério de gipsita e sob pressão manométrica acima da pressão atmosférica. Esse excedente de pressão foi obtido retendo-se parte do vapor produzido com a desidratação do minério, por meio de uma válvula do tipo alívio automático. A desidratação do minério de gipsita nessas condições dá origem a um gesso beta com características mecânicas superiores ao gesso convencionalmente produzido pela maioria dos processos
produtivos existentes no Pólo Gesseiro do Araripe, Pernambuco. Sob pressão controlada a 0,65 atm acima da pressão atmosférica e a aproximadamente 150 C, os cristais do gesso devem apresentar-se isentos de esfacelamentos, provocados pela saída abrupta da água combinada da molécula de gipsita ou di-hidrato do sulfato de cálcio. Foram testadas algumas importantes propriedades do gesso beta produzido sob a pressão manométrica proposta e comparadas aquelas obtidas de um gesso obtido sob condições convencionais de fabricação. Os testes verificaram valores da água de hidratação para confirmar a obtenção da conversão
da reação e de propriedades como massa unitária, módulo de ruptura à flexão, dureza e tempo de pega. Os gessos beta produzidos sob pressão foram testados em dois ciclos de vida e em ambos apresentaram características de um gesso com cristais bem formados, homogeneamente dispostos e de baixas porosidades inter- e intracristalina. Sua comparação
com gessos convencionais mostraram superioridade quanto às propriedades mecânicas, principalmente em relação a ambos em seus segundos ciclos de vida. Obteve-se um índice de
reciclagem de 100 %. Dessa forma, acredita-se que os processos produtivos industriais praticados no Pólo Gesseiro necessitam de intervenções técnicas, caso se deseje a reciclagem de parte dos gessos originados em resíduos das construções e demolições, tais como, placas para tetos, blocos para divisórias, gessos acartonados, etc., e aqueles também originados nos próprios processos de fabricação desses pré-moldadosOperational conditions of temperature and pressure had been determined under which the thermal dehydration of the gypsum ore occurs producing a type of recyclable beta plaster. With the resolution of the CONAMA n 307, of July 5th of 2002, the plaster waste proceeding from the civil building became one waste of difficult discarding, a time that this material is considered such as contaminante for the excessively component ones of a rubbish and considers that technology for its recycling still was not developed. In this work it was elaborated and confectioned a batch reactor in laboratory scale for beta plaster production from the ore gypsum and under pressure above of the atmospheric pressure. This excess of pressure was gotten holding back part of the water vapor produced with the dehydration of the ore, by means of a valve of the automatic relief type. The dehydration of the gypsum ore in these conditions gives origin to a beta plaster with superior mechanical characteristics to the plaster conventionally produced by the majority of the existing productive processes in the Polar Region Plasterer of the Araripe - Pernambuco. Under controlled pressure of 0.65 atm above of the atmospheric pressure and approximately 150 C, the plaster does not present breaked crystals, provoked for the abrupt exit of the dehydration water of the calcium sulphate di-hydrate. Some important properties of the beta plaster, produced under pressure had been tested and compared with plaster produced under conventional conditions of manufacture. The tests had verified values of the dehydration water, to confirm the final conversion of the dehydration reaction, and properties as unitary mass, flexion rupture modulus, hardness and setting time. The beta plasters produced under pressure had been tested in two life cycles and in both they had presented characteristics of a plaster with well formed crystals, homogeneously distributed and of low inter- and intra-crystals porosities. Its comparison with conventional plasters had shown superiority how much to the mechanical properties, mainly in relation to both in its second life cycles. The recycling index was of 100 %. So is given credit that the industrial productive processes practiced in the Polar Region Plasterer need technique adaptations, if it desires to the recycling of part of plasters originated in building and demolition, such as waste of the plates, blocks, plaster walls, and so on, and the wastes also originated in the proper processes of manufacture of these plaster premoldeds
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Ebadi, Arshia. "Communal Hall in Hackney Wick." Thesis, KTH, Arkitektur, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96948.
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Located in eastern London and beside the Olympic legacy there is this knotty hood, called Hackney Wick. A public realm has been proposed in the London Borough of Hackney local development masterplan for this neighbourhood. The project is a communal hall settled in the heart of this town context, has been challenged to tie with the dodgy surroundings. Coming from Olympic park, passing over the separating river and going to Victoria Park, is the main walking and cycling path. Also having the bus route on the same side, makes the northern side more exposed to the people. Facing the northern side of the site is the overground which generates views from the train to the project. As a result, in all the studied schemes, it has been tried to have a big opening looking towards this side. Observing the whole hood, you will find out the context is dominated by typical London brick walls, mostly filled with graffiti arts. This creates a special character for the area, and at the same time brings out some dodgy views. So the idea was to get benefit of the existing wall in the boundary of the site, as a tool to block the ugly views and create an inner paradise, and at the same time, with the aim of the brick nature of that wall, relate to the character of the context. However eventually, it ended up to propose to rebuild the wall with reused bricks, and cover the new added parts in white plaster. So finally, there would be this perception as if there is a new object over the existing, and the old brick wall remains at the bottom exposed to graffiti arts and keeps the same nature as it used to have.
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Guducu, Gulnur. "Archaeometrical Investigation Of Mud Plasters On Hittite Buildings In Sapinuwa-corum." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/1260751/index.pdf.
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The study aimed to identify mud brick and mud plaster technology of Hittites by examining some burnt mud brick walls of Shapinuwa Hittite city and to point out repair and conservation needs of those burnt mud brick structures.
The walls were documented by mapping the visual decay forms. The bulk density, total porosity, water absorption by capillarity and water vapour permeability were obtained as basic physical properties.
The mechanical properties were expressed by the modulus of elasticity and the uniaxial compressive strength. Compositional and mineralogical properties were determined by optical microscopy, XRD, TGA and SEM coupled with EDX, and by XRF analyses. In addition, pozzolanic activity of powdered samples was determined..
The samples studied had low bulk density, high porosity and high water vapour permeability. The Emod values and the UCS values showed that their mechanical properties were comparable with some historic mortars and bricks. The petrographic and mineralogical analyses of burnt materials indicated a mud brick composition containing fine and medium sized siliceous aggregates mainly composed of quartz. The binder was concluded to be composed of kaolinite illite and micritic calcite that indicated the use of ideal soil compositions by Hittites to make lime stabilized mud bricks, in terms of today standards.
The temperature during the fire was estimated to be around 700-800 C. The high pozzolanicity of burnt mud bricks and plasters, provided an opportunity to repair the structure using pozzolanic lime mortars to produce good adhesion. The first results of consolidation treatments had shown that the physical and mechanical properties of burnt mud brick can be improved by impregnation with ethylsilicates such as Tegovakon V.
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Brückner, Julian Karl. "Adhäsionskräfte von Artikulationsgipsen an Typ 3 und 4 Modellgips. Eine in vitro Studie." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-168928.
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Einleitung
Artikulationsgips dient der sicheren Verankerung von zahnärztlichen Gipsmodellen im Kausimulator. Eine Norm zur Quantifizierung der Haftfähigkeit dieses speziellen Dentalgipses an Gipsmodellen existiert bisher nicht. Ziel der vorliegenden Untersuchung ist es, Unterschiede zwischen Artikulationsgipsen bezüglich ihrer Adhäsion an Modellgipsen festzustellen und die neu entwickelte Methode zu bewerten.
Material und Methoden
Zur Untersuchung wurden die Artikulationsgipse dentona® arti-base® 60, piccodent® A 50, AmannGirrbach Artifix® und KerrTM Snow White Plaster No.2 an einen Typ 3 (dentona® dento dur® 110) und 4 Gips (dentona® sockel plaster® GT 160) gegossen. Die zylindrischen Prüfkörper enthielten zentrisch eingegossene Retentionen, die zur Verankerung in einer Universalprüfmaschine dienten. Prüfkörper aus Typ 3 und 4 Gips wurden vor dem Angießen des Artikulationsgipses 48 h getrocknet. Die Messung der Adhäsionskraft (in N) erfolgte mittels Zugversuch, 1 h nach der Erstarrung des Artikulationsgipses. Für jede Kombination wurden 10 Versuche durchgeführt. Die Datenauswertung erfolgte mittels t Test bei unabhängigen Stichproben und Dunnett´s T3 Vergleichstest (α=0,05).
Ergebnisse
Aus den 80 ermittelten Werten konnte ein Ranking der Gipskombinationen erstellt werden (Max. 1950,77 N, Min. 495,97 N). Es zeigten sich signifikante Unterschiede zwischen den einzelnen Kombinationen aus Modell- und Artikulationsgips. Innerhalb der Kombinationen mit Typ 3 Gips ergaben sich signifikante Unterschiede. Die Gruppen mit Typ 4 Modellgipses unterschieden sich hingegen nicht signifikant. Eine weitere Analyse zeigte bei zwei Artikulationsgipsen einen signifikanten Unterschied zwischen der Verwendung von Typ 3 und 4 Modellgips.
Schlussfolgerung
Es zeigte sich, dass die neu entwickelte Methode für die Untersuchung der Haftfähigkeit von Artikulationsgipsen geeignet ist. Aneinander gegossene Artikulations- und Modellgipse erreichen unterschiedlich hohe Adhäsionskräfte. Ein Vorteil für die Verwendung des Typ 3 gegenüber dem Typ 4 Modellgips ergab sich nicht. Am besten erschien in unserer Untersuchung die Kombination von dentona® dento dur® 110 und dentona® arti-base® 60.
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Zhu, Libing, and 朱麗冰. "Tianjiu therapy for patients with chronic asthma : an evaluation of efficacy and exploration of the optimal treatment duration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206740.
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Although Tianjiu Therapy in Sanfu Days (三伏天灸) is extensively being used for the treatment of asthma in Mainland China, there is a lack of convincing evidence to support its efficacy to expand its clinical application into asthma treatment. This study incorporated two related studies, the first was a randomized, double-blind, placebo-controlled trial with an aim to evaluate the efficacy of Tianjiu Therapy in Sanfu Days for patients suffering from chronic asthma. The second was a self-control clinical efficacy observation study aiming to compare the efficacy of 2 courses Tianjiu Therapy with 1 course such treatment in order to find the optimal duration of Tianjiu Therapy.
In the first study, 323 patients with chronic asthma were randomly assigned to Tianjiu Therapy group (n=165), and placebo group (n=158). There was no significant difference in primary and secondary outcome as compared with placebo group at the end of 3rd treatment and four times follow ups. But sub-analysis of secondary outcome in four times follow ups showed that Tianjiu Therapy significantly reduced the proportion of participants who didn’t need medical treatment during asthma attack increased from 6% to 15% at 1st follow up and 0% to 7% at 3rd follow up (P<0.05). In addition, Tianjiu Therapy was significantly superior to placebo in reducing the percentage of participants who were susceptibly waken up by asthma symptoms from 27% to 14%, and the percentage of participants who had the symptom of running nose and sneezing before onset from 18% to 8% at 2nd follow up ( P<0.05). Improvements also occurred with treatment group, it reduced the proportion of participants who were spontaneous sweating at 3rd follow up (P<0.05).
In the second study, totally 102 patients received two courses of Tianjiu Therapy (3 sessions Tianjiu Therapy in a year constituted one course of treatment). After treatment, the number of symptoms which were associated with Chinese Medicine added by 1.38 points (95% CI, 0.25 to 2.51), 2.93±0.41 in the 1 course group and 4.31±0.41 in the 2 courses group (P<0.05). The number of days with asthma-related symptoms increased by 3.05 points (95% CI, 0.37 to 5.73), 1.98±0.96 in 1 course group and 5.03±0.96 in 2 courses group (P<0.05). But both 1 course and 2 courses Tianjiu Therapy as compared with baseline (didn’t receive Tianjiu Therapy at this time point) have a significant improvement in the most outcome measurements.
From study 1, it was found that Tianjiu Therapy significantly decreased the need for pharmaceuticals to control asthma and improved the quality of participants’ life after one course Tianjiu Therapy. Study 2 indicated that although 2 courses Tianjiu Therapy was not as effective as 1 course Tianjiu Therapy in the treatment of asthma, both 1 course and 2 courses Tianjiu Therapy provided a significant improvement as compared with baseline. It was still unknown the optimal duration of Tianjiu Therapy, so it was worth to conduct the third course or more Sanfutianjiu Thearpy in future.published_or_final_version
Chinese Medicine
Master
Master of Philosophy
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Elmubarak, Mona Dr. "Accuracy and reliability of traditional measurement techniques for tooth widths and arch perimeter compared to CAD/CAM." The University of the Western Cpae, 2018. http://hdl.handle.net/11394/6472.
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Magister Scientiae Dentium - MSc(Dent)BACKGROUND: Plaster models form an integral part of the traditional orthodontic records. They are necessary for diagnosis and treatment planning, case presentations as well as for the evaluation of treatment progress. The accuracy of the measurements taken for space assessment is crucial prior to treatment planning. The introduction of digital models overcomes some problems experienced with plaster models. Digital models have shown to be an acceptable alternative for plaster models. AIM: The aim of the study was to determine the accuracy of traditional measurement techniques when compared to the CAD/ CAM measurements in the assessment of tooth widths and arch perimeter from plaster models. METHOD: The mesio-distal tooth widths and arch perimeter of thirty archived plaster models were measured using a digital caliper to the nearest 0.01 mm and divider to the nearest 0.1 mm. Corresponding digital models were produced by scanning them with a CAD/CAM (InEos X5) and space analysis completed by measurements using InEos Blue software. Measurements were repeated after 1 week from the initial measurement. The methods were compared using descriptive analysis (mean difference and standard deviation). RESULTS: The operator reliability was high for digital models as well as the plaster models when the measurement tool was the digital caliper (analyzed using the Pearson correlation coefficient in the paired t-test). The mean values of tooth widths measurements of CAD/CAM, digital caliper and divider were 6.82 (±0.04), 6.94 (± 0.04) and 7.11 (± 0.04). There was a significant difference between the measurements made by the CAD/CAM and the divider. Additionally significant differences between the measurements by digital caliper and divider measurements (p < 0.05) were observed. No significant difference was found when comparing CAD/CAM to digital caliper. Positive correlation was displayed between CAD/CAM, digital caliper and the divider, but the measurements completed with the digital caliper had the highest correlation with the CAD/CAM. The difference was not significant between the aforementioned measurement tools (p > 0.05). Arch perimeter measurements showed no statistical significant difference between CAD/CAM, digital caliper and divider (p < 0.05). CONCLUSION: Archived plaster models stored as records can be converted to digital models as it will have the same accuracy of measurements. The value of doing a space analysis with the CAD/CAM system can be performed with similar reliability on the digital models as a caliper on plaster models.
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Madhoo, Amika. "A comparison of three types of orthodontic study models." University of the Western Cape, 2020. http://hdl.handle.net/11394/8126.
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Magister Scientiae Dentium - MSc(Dent)The aim of this present study was to compare the accuracy of digital and printed study models with plaster study models, that are considered the gold standard. The objectives were to compare the accuracy of measurements obtained from digital and printed study models with those of plaster study models, to establish which type of study model yielded the most accurate measurements in comparison to plaster study models and to identify possible disadvantages and errors that can be made using any of the three types of study models.
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Krejčík, Jakub. "Analýza metod hodnocení špinivosti ETICS." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392328.
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This diploma thesis deals with problems of dirtiness of surface layers of ETICS (External thermal insulation contact system). In the theoretical part, soil damping agents and processes occurring when adhering dirt are described. The practical part then evaluates the impact of the aspects described below on their dirtyness. At the same time, it monitors the differences in staining depending on the type of material and the manufacturer. A methodology for artificial staining with controllable and repeatable conditions was developed in a special simulator, and this methodology was also verified practically. Simultaneously, individual plasters were exposed to the natural environment, for comparison of laboratory and actual conditions.
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Schaub, Henning. "Comparison of different aluminium casting processes from an environmental perspective : Case study on plaster mould castings produced in Mid Sweden." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35659.
Full textAbstract:
While Aluminium has lots of unique properties and is seen as a material of the future, its production and manufacturing has significant environmental impacts. For complex and dimensional shapes casting remains the main manufacturing method and in this study the environmental pressure of different casting techniques is compared. A screening LCA is conducted to determine the environmental impacts of plaster mould castings in a case study at the Ventana Hackås AB foundry in Mid Sweden. The findings are compared to models of sand, pressure die and lost wax castings, based on literature datasets. The most relevant factors for the environmental performance are identified as the production of the aluminium alloy and the amount and source of energy. For plaster mould castings additionally the plaster consumption is significant, while lost wax castings are dominated by the mould production and general processes. Under similar circumstances a relatively similar performance was found for all casting techniques except the lost wax process, which is at least 3 times more emission intensive. Of the remaining techniques pressure die castings performed the best and plaster mould castings the worst, but different sources of uncertainties have been identified in this comparison. In addition a carbon footprint interface is created based on these findings, to enable specific comparisons of different casting method setups. Customizable variables allow the adaptation of three scenarios to real world conditions. As the main influencing factors the aluminium alloy, source of electricity and casting technique have been identified.2018-10-10