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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Fabrication of nanomaterials from biomass for adsorption and antimicrobial applications

Uche, Cosmas Chinedu January 2020 (has links)
Philosophiae Doctor - PhD / The Black soldier fly (BSF) is an environmentally friendly and sustainable insect utilised in the decomposition of organic waste. This is due to its voracious consumption capability, disruptive functions and economic importance. The sustained global increase in commercial BSF farming has resulted in an expanded waste generation from its carcases to which beneficial uses ought to be developed. This study focused on the beneficial use of the generated waste by extracting chitosan from waste pupae and commercially reared BSF adult carcases. The study also considered the conversion of the extracted chitosan to nanofibres and nanoparticles for application in adsorption of inorganic Pb2+ or Cd2+ and antimicrobial studies, respectively. To achieve the aim of this study, the optimal extraction conditions of chitin and chitosan from both pupal exuviae and adult BSF waste materials were attained after a series of experiments. The extraction process involved three stages which were demineralisation, deproteination and deacetylation. The extracted adult and pupal chitin and chitosan were characterised using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction studies (XRD), high resolution scanning electron microscopy (HRSEM) and solid-state carbon nuclear magnetic resonance spectroscopy (13C NMR). Additionally, the adult (ACH20_9) and pupal (PCH21_9) chitosan samples, due to their solubility, were further characterised to determine their molecular weight, fat and water binding capacities, solubility and ash contents. / 2021-09-30
12

Optimisation and application of plant-based waste materials for the remediation of selected trace metals (Cd, Pb and Mn) and Oxyhalides (Bro3, CIO3 and IO3) in aqueous system

Abdulkadir, Muhammed Ibrahim 11 1900 (has links)
The research work is directed towards the investigation, optimization and application of some plant-based waste materials for the removal of some toxic trace metals (Cd, Pb and Mn) as well as selected oxyhalides (CIO3-,IO3- and BrO3-) in aqueous system. Waste materials from three plants; Athrixia philicoide, an indigenous bush tea; the outer covering peels of butternut Squash (Cucurbita Moschata) and pineapple (Ananas comosus) were evaluated for their sorption efficiency of the selected metals. batch and continuous experimental processes as well as conditions that might influence the sorption of the metals were investigated. These conditions include effects of pH sorption time, amount of adsorbent, volume of the aqueous medium, amount of metals etc. Qualitative and quantitative analysis of metal ions in solution was carried out using the ion chromatograph (IC) while the functional group identification present in waste materials was established using the Fourier Transform infr-red spectroscopy (FTIR), Quantitative biosorption equilibrium of 98.99% was reached within 6h at pH 6 and 100 ppm concentration of Pb metal with Athrixiaphilicoide under 30 min contact time. Applicability of the sorption process was tested on wastewater. Results revealed that > 99.93 %; 84.5 % and 64.3 % sorption efficiency was obtained for Mn, Cd and Pb respectively at pH 7 using Ananas Comosus adsorbent. For Athrixia philicoide, sorption efficiency from spiked wastewater ranged from 99.98 % for Cd; 99.96 % for Mn and 82.5 % adsorption for Pb at pH 7. For Juglans Cinerea, wastewater sorption efficiency varied between 78.76 %, 94.50 % and 96.50 % for Cd, Mn and Pb respectively at pH6. Results from the optimized method revealed the applicability of the method to environmental water samples. Possible large scale and industrial/commercial application of developed materials and methods would be explored. ) in aqueous system. Waste materials from three plants; Athrixia philicoide, an indigenous bush tea; the outer covering peels of butternut Squash (Cucurbita Moschata) and pineapple (Ananas comosus) were evaluated for their sorption efficiency of the selected metals. Batch and continuous experimental processes as well as conditions that might influence the sorption of the metals were investigated. These conditions include effects of pH, sorption time, amount of adsorbent, volume of the aqueous medium, amount of metals etc. Qualitative and quantitative analysis of metal ions in solution was carried out using the ion chromatograph (IC) while the functional group identification present in waste materials was established using the Fourier Transform infra-red spectroscopy (FTIR). Quantitative biosorption equilibrium of 96.99 % was reached within 6h at pH 6 and 100 ppm concentration of Pb metal with Athrixia philicoide under 30 min contact time. Cd and Mn adsorption by the same adsorbent under similar condition were less than 50 % for individual metal evaluation experiment. However, > 99 % adsorption was achieved with Cd in a mixture of the three (3) evaluated metals. Highest adsorption of 93 % of Pb was achieved with the Butternut Squash peel (Cucurbita moschata) at the optimal sorption pH of 6 followed by quantitative sorption of 99.2 % of Mn while Cd recorded a sorption level of 45 % all at 6 pH. The sorption efficiency of Pb, Cd and Mn using pineapple peels (Ananas comosus) also at the optimal sorption conditions of (pH 6, 30 min contact time and 100 ppm metal concentration) ranged from 98.7 %, 100 % and 99.90 % respectively. / Enviromental Science / M.Sc (Enviromental Science)
13

Återanvändning av textilt restmaterial / Recycling of textile waste materials

Englund, Angelica, Palm Samuelsson, Jessica, Tanemar, Olivia January 2013 (has links)
Detta arbete handlar om vad ett väletablerat företag skulle kunna göra med sitt restmaterial. Vi vet att det idag finns en mängd företag som jobbar för att minska sitt restmaterial och här presenteras förslag på vad man kan göra med det som ändå uppkommer. I arbetet presenterar vi först hur vi gått till väga för att samla in vår information, alltså hur vår forskning gjorts. Då arbetets syfte utgår ifrån Kasthall Mattor & Golv AB, har vi valt att presentera fakta kring företaget och hur deras syn ser ut på miljöarbete idag. För att förstå hur ett ökat miljöarbete påverkar ett företag har vi valt att fördjupa oss i CSR, Cradle to cradle, materialfakta och avfallshantering. Med hjälp av detta vill vi att läsaren lättare skall kunna följa vara tankar då förslagen presenteras samt diskuteras. I diskussionen analyseras detta sedan vidare med våra egna funderingar. Det tas också upp vad vi tycker om de olika förslagen och vilka fördelar respektive nackdelar vi ser att de har. I slutsatsen knyter vi samman arbetet med våra slutgiltiga tankar.This paper is about what a well-established company could do with their waste materials. We are aware of that today there are many companies working to reduce its waste materials and this paper presents suggestions for what to do with it. Firstly we present how we proceeded to gather our information. The purpose is based on Kasthall Mattor & Golv AB ́s waste problem and we have chosen to present the facts about the company and how they work with environmental questions today. To understand how an increased environmental work impacts a company we have chosen to immerse ourselves in CSR, Cradle to cradle, material facts, and waste management. Using this, we want to help the reader follow our thoughts when the proposals are presented and discussed. In the discussion we further analyze this with our own thoughts. It also looks at what we think about the various proposals and what advantages and disadvantages we find. In the conclusion we summarize the paper with our thoughts. / Program: Textil produktutveckling med entreprenörs- och affärsinriktning
14

Optimisation and application of plant-based waste materials for the remediation of selected trace metals (Cd, Pb and Mn) and Oxyhalides (Bro3, CIO3 and IO3) in aqueous system

Abdulkadir, Muhammed Ibrahim 11 1900 (has links)
The research work is directed towards the investigation, optimization and application of some plant-based waste materials for the removal of some toxic trace metals (Cd, Pb and Mn) as well as selected oxyhalides (CIO3-,IO3- and BrO3-) in aqueous system. Waste materials from three plants; Athrixia philicoide, an indigenous bush tea; the outer covering peels of butternut Squash (Cucurbita Moschata) and pineapple (Ananas comosus) were evaluated for their sorption efficiency of the selected metals. batch and continuous experimental processes as well as conditions that might influence the sorption of the metals were investigated. These conditions include effects of pH sorption time, amount of adsorbent, volume of the aqueous medium, amount of metals etc. Qualitative and quantitative analysis of metal ions in solution was carried out using the ion chromatograph (IC) while the functional group identification present in waste materials was established using the Fourier Transform infr-red spectroscopy (FTIR), Quantitative biosorption equilibrium of 98.99% was reached within 6h at pH 6 and 100 ppm concentration of Pb metal with Athrixiaphilicoide under 30 min contact time. Applicability of the sorption process was tested on wastewater. Results revealed that > 99.93 %; 84.5 % and 64.3 % sorption efficiency was obtained for Mn, Cd and Pb respectively at pH 7 using Ananas Comosus adsorbent. For Athrixia philicoide, sorption efficiency from spiked wastewater ranged from 99.98 % for Cd; 99.96 % for Mn and 82.5 % adsorption for Pb at pH 7. For Juglans Cinerea, wastewater sorption efficiency varied between 78.76 %, 94.50 % and 96.50 % for Cd, Mn and Pb respectively at pH6. Results from the optimized method revealed the applicability of the method to environmental water samples. Possible large scale and industrial/commercial application of developed materials and methods would be explored. ) in aqueous system. Waste materials from three plants; Athrixia philicoide, an indigenous bush tea; the outer covering peels of butternut Squash (Cucurbita Moschata) and pineapple (Ananas comosus) were evaluated for their sorption efficiency of the selected metals. Batch and continuous experimental processes as well as conditions that might influence the sorption of the metals were investigated. These conditions include effects of pH, sorption time, amount of adsorbent, volume of the aqueous medium, amount of metals etc. Qualitative and quantitative analysis of metal ions in solution was carried out using the ion chromatograph (IC) while the functional group identification present in waste materials was established using the Fourier Transform infra-red spectroscopy (FTIR). Quantitative biosorption equilibrium of 96.99 % was reached within 6h at pH 6 and 100 ppm concentration of Pb metal with Athrixia philicoide under 30 min contact time. Cd and Mn adsorption by the same adsorbent under similar condition were less than 50 % for individual metal evaluation experiment. However, > 99 % adsorption was achieved with Cd in a mixture of the three (3) evaluated metals. Highest adsorption of 93 % of Pb was achieved with the Butternut Squash peel (Cucurbita moschata) at the optimal sorption pH of 6 followed by quantitative sorption of 99.2 % of Mn while Cd recorded a sorption level of 45 % all at 6 pH. The sorption efficiency of Pb, Cd and Mn using pineapple peels (Ananas comosus) also at the optimal sorption conditions of (pH 6, 30 min contact time and 100 ppm metal concentration) ranged from 98.7 %, 100 % and 99.90 % respectively. / Enviromental Science / M.Sc (Enviromental Science)
15

Reaproveitamento de residuos de chumbo na fabricação de placas de acumuladores eletricos automotivos / Reuse of wasate lead in the manufacture of electrical automotive accumulators

Dias, Marcelo 02 November 2010 (has links)
Orientador: Sergio Tonini Button / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-15T16:59:07Z (GMT). No. of bitstreams: 1 Dias_Marcelo_M.pdf: 766952 bytes, checksum: fe095b522c7769ed98d42e60deea261d (MD5) Previous issue date: 2010 / Resumo: Nas últimas décadas, a concorrência entre as indústrias vem ficando cada vez mais acirrada. Tem-se visto um movimento mundial no sentido de melhorar a competitividade, através de melhorias de qualidade nos produtos e serviços, redução de custos através da melhoria da produtividade, redução de quadro de pessoal e aumento da eficiência dos processos. O atendimento às normas e legislação ambientais também tem contribuído para a imagem das companhias, atuando a favor da sua competitividade. As empresas produtoras de baterias automotivas têm uma margem de lucro bastante reduzida por unidade produzida, portanto precisam produzir em larga escala, para serem lucrativas. A variabilidade dos processos, tanto administrativos quanto industriais, provoca desvios e gastos de recursos desnecessários, que devem ser eliminados. A intenção deste trabalho é demonstrar como ferramentas estatísticas podem ser utilizadas para reduzir a quantidade de borra de ligas de chumbo enviada para reciclagem externa, gerada na fundição de bobinas para a expansão de grades de baterias automotivas, através da utilização da filosofia Seis Sigma. O objetivo do trabalho foi atingido como se pode observar pela expressiva redução do nível de PPM atingido e sua conseqüente redução de custo. A redução de 55,4 % na quantidade de borra gerada significou menos resíduos de chumbo em circulação nas estradas e menos manuseio do material que, embora transportado na fase metálica, possui uma parte que se oxida e fica na forma de pó. / Abstract: In recent decades, the competition between industries is becoming increasingly fierce. It has seen a worldwide movement to improve competitiveness through quality improvements in products and services, reducing costs by improving productivity, reducing staff and increasing the efficiency of processes. The service standards and environmental legislation has also contributed to the image of companies, acting in favor of its competitiveness. The manufacturers of automotive batteries have a profit margin greatly reduced per unit of output, so they must produce on a large scale to be profitable.The variability of processes, both administrative and industrial to deflections and spending unnecessary resources, which must be eliminated. The intention of this work is to demonstrate how statistical tools can be used to reduce the amount of sludge lead alloys sent for recycling outside, generated in the casting reels for expanding grids of automotive batteries through the use of Six Sigma philosophy. The objective was achieved as shown by the significant reduction in the level of PPM achieved and the consequent cost reduction. The 55.4% reduction in the amount of sludge generated meant less waste lead in circulation on the roads and less handling of material that, while carried in metallic phase, has some rust and it is in powder form. / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
16

Ekotoxikologické hodnocení vybraných průmyslových odpadních materiálů a anorganických kompozitů s jejich obsahem / Ecotoxicological Evaluation of Industrial Waste Materials and Anorganic Composites Containing Waste Materials

Pavlitová Letková, Zuzana January 2011 (has links)
This work sums up results of tests of ecotoxicity that were made on different kind of industrial waste materials like classical ash, fluid and fly ash, slags as well as anorganic composites containing waste materials. Composites might be used for building materials in the future. Ecotoxicological tests were used for evaluation of ecotoxicity, represented by 4 trophic levels, with several bioindicators evaluated at different exposure time periods. The battery of classical tests includes a growth inhibition test of the freshwater alga Raphidocellis subcapitata, an immobilization test of the cladoceran Daphnia magna and freshwater fish Poecilia reticulata and a test of inhibitive effects on the root growth of white mustards Sinapis alba. Tests with enchytraeidae, collembolan and lettuce were chosen from group of contact tests. It was realized confrontation between classical test with seeds of mustard and contact tests with seeds of lettuce. Results of ecotoxicity tests were determination of percentage of mortality, immobilization, stimulation or inhibition of growth for testing organisms. It was made comparison of results individual ecotixicity tests. Results of classical aquatic tests were compared with contact tests realized in artificial ground.
17

Vývoj nových průmyslových podlah s využitím druhotných surovin / Development of industrial floors with utilization of by-product

Radějová, Lucie Unknown Date (has links)
This work deals with the use of waste materials in the development of new industrial floors. The main task of this work is to choose a suitable waste materials, and design a new material using such materials, while achieving the required physico-mechanical properties. The aim of this work is also to verify the effects of process application, suitable microfiller and final coat and propose a suitable alternative industrial floors, which would not only be in terms of economic efficiency, but also in terms of ecological suitable replacement for commercial products.
18

Beneficial Reuse of Corrugated Paperboard in Civil Engineering Applications

Stone, Gregory M 01 March 2012 (has links) (PDF)
Abstract Beneficial Reuse of Corrugated Paperboard in Civil Engineering Applications Gregory Michael Stone An investigation was conducted to explore the potential for reuse of corrugated paperboard. Corrugated paperboard represents a large fraction of the municipal solid waste generated and discarded in the United States. Alternative applications for reuse can provide a significant benefit by reducing the volume of waste being disposed and by reducing the use of raw materials. Four civil engineering applications were examined for potential beneficial reuse of corrugated paperboard: slurry trench construction, vertical drilling, directional drilling, and controlled low strength materials (CLSM). For the purpose of this project, corrugated paperboard was pulped and added to bentonite slurry or CLSM mixtures. Bentonite slurry mixtures were tested for viscosity, density, filtrate loss, and permeability. The behavior of the bentonite slurries was greatly influenced by interaction and interlocking of corrugate fibers; in general resulting in increased viscosity, filtrate loss, and permeability and decreased density. CLSM mixtures were tested for flow consistency, unit weight, air content, and compressive strength. CLSM mixtures prepared with corrugated paperboard showed an increased water demand due to high absorption of the corrugate. The higher water content was a significant factor contributing to decreased unit weight and compressive strength. CLSM mixtures containing corrugated paperboard also exhibited increased air contents, possibly due to entrapment of air within the corrugate pulp. Corrugated paperboard was used to successfully replace up to 27% of bentonite for slurry trench applications, 60% of bentonite for vertical drilling applications, and 59% of bentonite for directional drilling applications while maintaining acceptable engineering properties. For CLSM mixtures up to 1% of fine aggregate was replaced with corrugated paperboard while maintaining satisfactory engineering properties. Incorporation of corrugated paper board into bentonite slurry, CLSM, and drilling fluid applications provides a viable option for beneficial reuse.
19

Synthesis of portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance

Chen, Irvin Allen 01 June 2010 (has links)
Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, Portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, 1.) incorporation of waste materials in portland cement synthesis, and 2.) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S–C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate-belite cement that contained medium C4A3 S and C2S contents showed good dimensional stability, sulfate resistance, and compressive strength development and was considered the optimum phase composition for calcium sulfoaluminate-belite cement in terms of comparable performance characteristics to portland cement. Furthermore, two calcium sulfoaluminate-belite cement clinkers were successfully synthesized from natural and waste materials such as limestone, bauxite, flue gas desulfurization sludge, Class C fly ash, and fluidized bed ash proportioned to the optimum calcium sulfoaluminate-belite cement synthesized from reagent-grade chemicals. Waste materials composed 30% and 41% of the raw ingredients. The two calcium sulfoaluminate-belite cements synthesized from natural and waste materials showed good dimensional stability, sulfate resistance, and compressive strength development, comparable to commercial portland cement. / text
20

Estudo da utilização de agregado reciclado em misturas de concreto de cimento Portland para pavimentação / A study of using recycled aggregates in Portland concrete mixes for pavements

Barbosa Junior, Alvaro Sergio 12 August 2018 (has links)
Orientador: Rita Moura Fortes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-12T06:54:45Z (GMT). No. of bitstreams: 1 BarbosaJunior_AlvaroSergio_M.pdf: 1121830 bytes, checksum: e02fb4a353bc75b1933fd3e74153b6ea (MD5) Previous issue date: 2008 / Resumo: O objetivo da presente pesquisa e apresentar uma contribuição ao estudo da utilização de agregados reciclados em misturas de concreto de cimento Portland (CCP) para pavimentação. São comparados os desempenhos de misturas utilizando-se agregados oriundos do gnaisse e também do entulho de laboratórios de controle tecnológico, para avaliar o potencial de sua utilização, minimizando a sua problemática deposição em aterros sanitários, contribuindo dessa maneira para a preservação do meio ambiente. Os agregados originados pela moagem desses entulhos serão estudados separadamente, ou seja, os provenientes de corpos de prova de concreto, de blocos de concreto e blocos de materiais cerâmicos. Pretende-se conhecer o potencial de utilização desse material reciclado como agregado contribuindo para a preservação do meio ambiente. E importante enfatizar que este material e de boa qualidade e tem sido usualmente descartado, ou melhor, desperdiçado. Este trabalho avalia os resultados levando em conta a sua seleção, dosagem e mistura, de maneira a atender as propriedades necessárias para a pavimentação / Abstract: The objective of this research is to contribute to the study of the recycled aggregate use in concrete Portland. It is compared the performance of these mixtures presented with the deriving aggregates and the rubbish of technological control laboratories, which the use minimizes the problematic deposition in sanitary earthworks, contributing in this way to the environment's preservation. The aggregates originated for the milling of these tested specimens will be studied separately, in other words, the preceding from specimens of concrete test, of concrete blocks and ceramic materials. In this research is studied the potential use of these recycled materials as aggregate contributing for the environment preservation. It is important to emphasize that this material presents good quality and is usually discarded or wasted. This paper evaluates the results taking into account the selection and mixing for the adequate pavement properties. / Mestrado / Transportes / Mestre em Engenharia Civil

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