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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.
21

Preparation And Characterization Of Organoclay-polypropylene Nanocomposites With Maleic Anhydride Grafted Polypropylene Compatibilizer

Yilmaz, Sule Seda 01 June 2011 (has links) (PDF)
The aim of this study was to improve the mechanical properties &ldquo / Moplen&rdquo / EP300L which is a heterophase copolymer. Polymer blends and nanocomposites were prepared by melt compounding method in a twin screw extruder. Nanofil&reg / 5 (N5) and Nanofil&reg / 8(N8) were used as the organoclays, and maleic anhydride grafted polypropylene (M) was used as the compatibilizer. The effects of additive concentrations and types of organoclays on the morphology, mechanical and thermal properties were investigated. Organoclay loading over 2 wt% prevented the intercalation mechanism resulting in large aggregates of clay, thus the material properties became poor even in the presence of compatibilizer. Compatibilizer addition improved the intercalation ability of the polymer, however a substantial increase in mechanical properties was not obtained up to 6 wt % loading of the compatibilizer. XRD analysis revealed that intercalated structures were formed with the addition of compatibilizer and organoclay. The nanocomposites that were prepared with N5 type organoclay showed delaminated structures at 6 wt % compatibilizer loading. v Nanofill &reg / 5 exhibited the highest improvements in mechanical properties, since the degree of organoclay dispersion was better in Nanofill &reg / 5 containing nanocomposites in comparison to Nanofill &reg / 8 containing ones. The DSC analysis indicated a insignificant reduction in the melting temperature of the ternary nanocomposites.
22

The Easter Rising : Pearse, print, and the modern Irish elegy

Ward, Thomas Barrett 19 December 2013 (has links)
The 1916 Easter Rising was the watershed political moment of the modern Irish Nation. Padraig Pearse, along with his co-conspirators, initiated an event that dramatically affected the Celtic Revival literary movement. Prior to the rebellion, Pearse left a calculated literary legacy through pamphlets, broadsides, and poems. His most notable contribution to print nationalism was the text of The Easter Proclamation, but the poems he wrote prior to his execution are important contributions to the modern Irish elegiac tradition. Poets took to their work with renewed political fervor and used elegiac forms to mourn the dead and subvert the rhetoric of imperialism. This study focuses on the modern Irish elegy, but also records the creation and reception of Pearse’s documents and actions. Beginning with his political pamphlets, speeches, and poetry, this paper examines how Pearse’s legacy in print impacted the elegiac tradition in Ireland. While it would be impossible to examine every elegy directly influenced by the Easter Rising in this short paper, it is useful to examine disparate elegiac viewpoints on this historical event. Initially tracing the historical production of The Easter Proclamation and Pearse’s series of separatist pamphlets, this exploration shifts to Pearse’s self-elegies and the elegies written by his acquaintances and contemporaries. Yeats is the obvious starting point for Republican elegies, but I will also explore the shifting poetics and elegiac tropes present in the poems of AE (George Russell), and Francis Ledwidge. This paper does not seek to ignore or discredit the print legacy of the other leaders of the Rising (notably Connolly, MacDonagh, and Markiewicz), but focuses on Pearse because of his print legacy and political importance. / text
23

Numerical Simulations Of Unsteady Flow In An Oil Pipeline Under Various Hydraulic Conditions

Turan, Emrah 01 April 2006 (has links) (PDF)
In the present study,transint flow analyses of a long oil pipeline are performed.
24

Monitoring gas void fraction in two-phase flow with acoustic emission

Addali, Abdulmajid January 2010 (has links)
The two-phase gas/liquid flow phenomenon can be encountered over a range of gas and liquid flow rates in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Monitoring and measurement of their characteristics, such as the gas void fraction, are necessary to minimise the disruption of downstream process facilities. Thus, over the last decade, the investigation, development and use of multiphase flow metering system have been a major focus for the industry worldwide. However, these meters suffer from several limitations in some flow conditions such as Slug flow regime. This research presents experimental results correlating Acoustic Emission measurements with Gas Void Fraction (GVF) in a two-phase air / water flow. A unique experimental facility was modified to accommodate an investigation into the applicability of the Acoustic Emission (AE) technology in monitoring two-phase gas\liquid flow. The testing facility allowed for investigations over a range of superficial liquid velocities (0.3 to 2.0 ms-1) and superficial gas velocities (0.2 to 1.4 ms-1). The influence of several variables such as temperature, viscosity and surface roughness were also investigated. Measurements of AE for varying gas void fractions were compared to conductive probe measurements and results showed a direct correlation between the AE energy and the gas void fraction. It is concluded that the GVF can be determined by measurement of Acoustic Emission and this forms the major contribution of this thesis.
25

Long Term Health Monitoring of Anthony Wayne Bridge Main Cable with Acoustic Emission Technique

Seyedianchoobi, Rasa 22 August 2013 (has links)
No description available.
26

Návrh a ověření funkce stanice pro kalibraci snímačů AE při testování ložisek / Design and verification of station for calibration of AE sensors for bearing testing

Bančák, Matej January 2017 (has links)
The diploma thesis deals with calibration of AE sensors used in diagnostics of bearings. Two different conceptual solutions similar to those used in the diagnostics of bearings were designed in the design. Subsequently, the experimental device was designed for relative calibration using the rotation of bearings as a continuous AE source. The experimental part is oriented to the observation of the RMS parameter, which serves as a sensor sensitivity evaluation parameter. As sources of AE, bearings with a certain type of damage were used, which allowed for the formation of sensitivity characteristics according to the type of damage. Sensitivity characteristics of selected AE sensors have been developed to determine the effectiveness in relative calibration. The exponential sensitivity sensitivity of the MDK-13 sensors was observed on the software amplification of the AE analyzer. A proposal for the calibration method for MDK-13 type sensors was developed on the principle of comparison with the reference sensor.
27

Caracterização da comunidade microbiana de reator anaeróbio de leito fluidificado envolvida na degradação de surfactante não iônico álcool etoxilado de cadeia não ramificada (GENAPOL) / Microbial characterization of anaerobic fluidized bed reactor involved in the nonionic surfactant alcohol ethoxylate non-branched (GENAPOL) degradation

Motteran, Fabricio 13 December 2013 (has links)
O objetivo deste estudo foi avaliar a remoção do surfactante não iônico álcool etoxilado de cadeia não ramificada (AE) em reator anaeróbio de leito fluidificado preenchido com areia como material suporte, em escala de bancada (1,2 L) com TDH de 18 horas, recirculação e fluxo contínuo. O reator foi inoculado com lodo proveniente de reator UASB utilizado no tratamento de dejetos de suinocultura e alimentado com substrato sintético acrescido de surfactante não iônico GENAPOL® C-100 (Sigma-Aldrich®) como fonte de (AE). Análises de monitoramento da concentração do surfactante não iônico AE e matéria orgânica, bem como, dos parâmetros físico-químicos foram realizadas para observar e quantificar a estabilidade do reator, na remoção e degradação do surfactante. A operação do reator foi dividida em cinco etapas: inoculação (535±121 mg/L de DQO), adaptação da biomassa (600±70 mg/L de DQO), Fase I (4,7 mg/L de AE e 623±65 mg/L de DQO), Fase II (22,5 mg/L de AE e 735±87 mg/L de DQO), Fase III (51,4 mg/L de AE e 697±68 mg/L de DQO), Fase IV (107,4 mg/L de AE e 845±87 mg/L de DQO) e Fase V (97,9 mg/L de AE e 882±126 mg/L de DQO). Aplicação das técnicas de PCR/DGGE e pirosequenciamento da região do rRNA 16S foi realizada para constatar a diversidade microbiana nas fases operacionais IV e V. A eficiência média de remoção de matéria orgânica e AE foi de 88% e 99%, respectivamente, durante a operação do reator. A similaridade das populações dos Domínios Archaea e Bacteria foi de 74% e 59%, respectivamente, para as amostras da Fase IV (com sacarose) e Fase V (sem sacarose). A sacarose não alterou o comportamento físico-químico do reator de leito fluidificado, mas este co-substrato influenciou, tanto, na produção de ácidos orgânicos voláteis, quanto, na diversidade dos microrganismos envolvidos na degradação do AE. Por meio da análise de pirosequenciamento das amostras das Fases IV e V do material suporte e separador de fases do reator foram identificados 83 gêneros dos quais 18 foram relacionados com a degradação de surfactante não iônico, bem como, seus subprodutos. Obteve-se maior abundância relativa para os seguintes gêneros: Sporomusa, Geobacter, Desulfobulbus, Synergistes, Sedimentibacter, Holophaga, Serpens e Azonexus. Observou-se elevada diversidade filogenética e similaridade com sequências de bactérias relacionadas com a degradação de surfactante não iônico AE. / The aim of this study was to evaluate the removal of nonionic alcohol ethoxylate non-branched (AE) in anaerobic fluidized bed reactor filled with sand as support material, on a bench scale (1.2 L) with 18 hours of TDH, recirculation and continuous flow. The reactor was inoculated with sludge from a UASB reactor used in the treatment of swine manure and fed with synthetic substrate plus nonionic GENAPOL® C-100 (Sigma-Aldrich®) as a source of AE. Monitoring analysis of the nonionic surfactant AE concentration and organic matter, as well as the physicochemical parameters were performed to observe and quantify the reactor stability, in the removal and degradation of the surfactant. The reactor operation was divided into five phases: inoculation (535±121 mg/L of COD), biomass adaptation (600±70 mg/L of COD), Phase I (4,7 mg/L of AE and 623±65 mg/L of COD), Phase II (22,5 mg/L of AE and 735±87 mg/L of COD), Phase III (51,4 mg/L of AE and 697±68 mg/L of COD), Phase IV (107,4 mg/L of AE and 845±87 mg/L of COD) and Phase V (97,9 mg/L of AE and 882±126 mg/L of COD). Application of the techniques PCR/DGGE and pyrosequencing of the 16S rRNA region were performed to observe the microbial diversity in the operational phases IV and V. The average removal efficiency of organic matter and AE was 88% and 99%, respectively, during the reactor operation. The populations similarity of the Archaea and Bacteria Domains were 74% and 59%, respectively, for samples from Phase IV (with sucrose) and Phase V (without sucrose). Sucrose did not alter the physical-chemical behavior of the fluidized bed reactor, but this co-substrate influenced both in the volatile fatty acids production, as in the diversity of microorganisms involved in the AE degradation. Through the pyrosequencing analysis of samples from Phases IV and V of the reactor (support material and phase separator), 83 genera were identified of which 18 were related to the nonionic surfactant degradation, as well as its byproducts. Highest relative abundance values were obtained for the following genera: Sporomusa, Geobacter, Desulfobulbus, Synergistes, Sedimentibacter, Holophaga, Serpens and Azonexus. A high phylogenetic diversity and similarity to sequences of bacteria related to the degradation of nonionic AE surfactant were observed.
28

Evaluation of the Removal Efficiency of Per- and Polyfluoroalkyl Substances in Drinking Water using Nanofiltration Membranes, Active Carbon and Anion Exchange / Utvärdering av reningseffektiviteten av per- och polyfluorerade alkylsubstanser i dricksvatten med nanofiltrering, aktivt kol och jonbytarmassa

Lindegren, Klara January 2015 (has links)
Per- and polyfluoroalkyl substances (PFASs) is a group of man-made, highly persistent chemicals. Due to the specific surface-active attributes of these molecules, applications are numerous and feed an economically important industry. During the last decade, PFASs have been detected globally in the environment, living organisms and tap water. The combination of toxic properties and high bioaccumulative potential, together with the discovery that conventional water treatment methods do not remove PFAS, renders further research on purification methods highly needed.  Three techniques of purifying water from PFASs were examined. Nanofiltration technology (NF) is a membrane filtration technique, which produces a purified product (the permeate) by generating an effluent of high contaminant concentration (the reject water). To decontaminate the reject water, adsorption by granular activated carbon (GAC) or anion exchange (AE) have been proposed. The efficiency of these three technologies was studied at Bäcklösa drinking water treatment plant (DWTP) in Uppsala. A nanofiltration pilot with two 270NF membranes (Dow Filmtech™), connected in series, was used. A high removal efficiency (>90%) was found for all PFASs. Furthermore, it was confirmed that the concentration in the permeate water was a function of the concentration in the incoming raw water; increased PFAS raw water concentration resulted in increased PFAS permeate concentration. Size-exclusion and electrostatic repulsion were deemed important mechanisms. For the comparison of GAC (Filtrasorb 400®) and AE (Purolite® A-600), a column experiment was set up. The perfluoroalkane (-alkyl) sulfonic acids (PFSAs) and perfluorooctanesulfonamide (FOSA) had similar removal efficiencies using both GAC and AE, and the efficiency increased with increasing chain length. AE was found to have a higher average removal efficiency of perfluoroalkyl carboxylic acid (PFCAs) (62-95%) than GAC (49-81%). In conclusion, longer chain length PFASs were removed more effectively than shorter-chained, and the PFSAs and FOSA showed higher removal efficiency compared to the PFCAs. Furthermore, linear isomers were removed more effectively than branched for GAC and AE. In contrast, the opposite was found for the NF membrane, where branched isomers were better retained. / Per- och polyfluorerade alkylsubstanser (PFAS) är en grupp syntetiska, ytterst persistenta kemikalier. På grund av deras ytaktiva egenskaper är de lämpliga för användning i många produkter och tillverkningsprocesser, och är således viktiga för en ekonomiskt betydande industri. Under det senaste årtiondet har PFAS påträffats i miljön, levande organismer och kranvatten världen över.  Kombinationen av toxiska egenskaper, en hög bioackumuleringspotential och upptäckten att konventionella reningsmetoder inte avlägsnar substanserna från vatten, gör att vidare forskning av reningsmetoder för PFAS är mycket angelägen. Tre reningsteknikers förmåga att rena vatten från PFAS undersöktes. Nanofiltrering (NF) är en membranfiltreringsteknik som utöver den renade produkten, permeatet, även framställer en biprodukt av hög föroreningsgrad, rententatet. För att rena rententatet har adsorption till granulärt aktivt kol (GAC) eller jonbytarmassa (AE) föreslagits. Teknikerna utvärderades på Bäcklösa Vattenverk i Uppsala.  Nanofiltreringen undersöktes i en pilotanläggning där två 270NF (Dow Filmtech™) membran var seriekopplade. En hög reningsgrad (>90%) konstaterades för alla typer av PFAS. Vidare visades PFAS-koncentrationen i permeatet vara en funktion av PFAS-koncentrationen i råvattnet; en ökad råvattenkoncentration gav en ökad permeatkoncentration. Storleksseparation och elektrostatisk repulsion befanns vara viktiga mekanismer som påverkade reningsgraden. För att undersöka de mekanismer som påverkar PFAS-adsorption jämfördes GAC (Filtrasorb 400®) och AE (Purolite® A-600) i ett kolonnexperiment. Reningsgraden för GAC och AE av perfluorerade sulfonsyror (PFSA) och perfluorooktan sulfonamider (FOSA) var lika hög och reningseffektiviteten ökade med ökande kolkedjelängd. AE återfanns ha en högre genomsnittlig reningsgrad av perfluorkarboxylsyror (PFCA) (62-95%) än GAC (49-81%). Sammanfattningsvis avlägsnades PFAS av längre kolkedjelängd mer effektivt än kortare kolkedjor, och PFAS med sulfonsyror och sulfonamider som funktionella grupper uppvisade en högre reningsgrad än karboxylsyrorna. Vidare renades linjära isomerer mer effektivt än grenade både genom GAC och AE. Däremot konstaterades det motsatta för NF-membranen, där grenade isomerer renades mer effektivt. / SafeDrink
29

Caracterização da comunidade microbiana de reator anaeróbio de leito fluidificado envolvida na degradação de surfactante não iônico álcool etoxilado de cadeia não ramificada (GENAPOL) / Microbial characterization of anaerobic fluidized bed reactor involved in the nonionic surfactant alcohol ethoxylate non-branched (GENAPOL) degradation

Fabricio Motteran 13 December 2013 (has links)
O objetivo deste estudo foi avaliar a remoção do surfactante não iônico álcool etoxilado de cadeia não ramificada (AE) em reator anaeróbio de leito fluidificado preenchido com areia como material suporte, em escala de bancada (1,2 L) com TDH de 18 horas, recirculação e fluxo contínuo. O reator foi inoculado com lodo proveniente de reator UASB utilizado no tratamento de dejetos de suinocultura e alimentado com substrato sintético acrescido de surfactante não iônico GENAPOL® C-100 (Sigma-Aldrich®) como fonte de (AE). Análises de monitoramento da concentração do surfactante não iônico AE e matéria orgânica, bem como, dos parâmetros físico-químicos foram realizadas para observar e quantificar a estabilidade do reator, na remoção e degradação do surfactante. A operação do reator foi dividida em cinco etapas: inoculação (535±121 mg/L de DQO), adaptação da biomassa (600±70 mg/L de DQO), Fase I (4,7 mg/L de AE e 623±65 mg/L de DQO), Fase II (22,5 mg/L de AE e 735±87 mg/L de DQO), Fase III (51,4 mg/L de AE e 697±68 mg/L de DQO), Fase IV (107,4 mg/L de AE e 845±87 mg/L de DQO) e Fase V (97,9 mg/L de AE e 882±126 mg/L de DQO). Aplicação das técnicas de PCR/DGGE e pirosequenciamento da região do rRNA 16S foi realizada para constatar a diversidade microbiana nas fases operacionais IV e V. A eficiência média de remoção de matéria orgânica e AE foi de 88% e 99%, respectivamente, durante a operação do reator. A similaridade das populações dos Domínios Archaea e Bacteria foi de 74% e 59%, respectivamente, para as amostras da Fase IV (com sacarose) e Fase V (sem sacarose). A sacarose não alterou o comportamento físico-químico do reator de leito fluidificado, mas este co-substrato influenciou, tanto, na produção de ácidos orgânicos voláteis, quanto, na diversidade dos microrganismos envolvidos na degradação do AE. Por meio da análise de pirosequenciamento das amostras das Fases IV e V do material suporte e separador de fases do reator foram identificados 83 gêneros dos quais 18 foram relacionados com a degradação de surfactante não iônico, bem como, seus subprodutos. Obteve-se maior abundância relativa para os seguintes gêneros: Sporomusa, Geobacter, Desulfobulbus, Synergistes, Sedimentibacter, Holophaga, Serpens e Azonexus. Observou-se elevada diversidade filogenética e similaridade com sequências de bactérias relacionadas com a degradação de surfactante não iônico AE. / The aim of this study was to evaluate the removal of nonionic alcohol ethoxylate non-branched (AE) in anaerobic fluidized bed reactor filled with sand as support material, on a bench scale (1.2 L) with 18 hours of TDH, recirculation and continuous flow. The reactor was inoculated with sludge from a UASB reactor used in the treatment of swine manure and fed with synthetic substrate plus nonionic GENAPOL® C-100 (Sigma-Aldrich®) as a source of AE. Monitoring analysis of the nonionic surfactant AE concentration and organic matter, as well as the physicochemical parameters were performed to observe and quantify the reactor stability, in the removal and degradation of the surfactant. The reactor operation was divided into five phases: inoculation (535±121 mg/L of COD), biomass adaptation (600±70 mg/L of COD), Phase I (4,7 mg/L of AE and 623±65 mg/L of COD), Phase II (22,5 mg/L of AE and 735±87 mg/L of COD), Phase III (51,4 mg/L of AE and 697±68 mg/L of COD), Phase IV (107,4 mg/L of AE and 845±87 mg/L of COD) and Phase V (97,9 mg/L of AE and 882±126 mg/L of COD). Application of the techniques PCR/DGGE and pyrosequencing of the 16S rRNA region were performed to observe the microbial diversity in the operational phases IV and V. The average removal efficiency of organic matter and AE was 88% and 99%, respectively, during the reactor operation. The populations similarity of the Archaea and Bacteria Domains were 74% and 59%, respectively, for samples from Phase IV (with sucrose) and Phase V (without sucrose). Sucrose did not alter the physical-chemical behavior of the fluidized bed reactor, but this co-substrate influenced both in the volatile fatty acids production, as in the diversity of microorganisms involved in the AE degradation. Through the pyrosequencing analysis of samples from Phases IV and V of the reactor (support material and phase separator), 83 genera were identified of which 18 were related to the nonionic surfactant degradation, as well as its byproducts. Highest relative abundance values were obtained for the following genera: Sporomusa, Geobacter, Desulfobulbus, Synergistes, Sedimentibacter, Holophaga, Serpens and Azonexus. A high phylogenetic diversity and similarity to sequences of bacteria related to the degradation of nonionic AE surfactant were observed.
30

Diagnosis of Pneumatic Cylinders Using Acoustic Emission Methods / Diagnosis of Pneumatic Cylinders Using Acoustic Emission Methods

Mahmoud, Houssam January 2019 (has links)
Tato práce se zabývá vývojem nového efektivního diagnostického postupu pro kontrolu funkce pneumatických válců pomocí metody akustické emise. Cílem práce bylo navrhnout a určit diagnostická kritéria pro hodnocení kvality vybraných typů pneumatických válců. Prvním krokem bylo nalezení typického akustického emisního signálu, který je spojen s určitým typem poškození ve válci využitím frekvenčního spektra signálu. Později byl tento parametr nahrazen parametrem RMS během sledování změn v průběhu testů. Na konkrétních válcích byl sledován vztah mezi akustickou emisí a různými typy defektů a byl představen nový přístup k určování těchto typů vad a jejich odlišením v signálu akustické emise. Druhý krok studie že neporušené a poškozené válce byly porovnávány tak, aby se zjistily výrazné rozdíly, které určují, zda je válec poškozen nebo nepoškozen. Několik nepoškozených válců bylo testováno akustickou emisí a následně v nich byly vytvořeny umělé vady. Signály z vysouvání a zasouvání pístu byly zaznamenány a analyzovány pomocí řady parametrů. Na základě časového zpoždění a normalizace RMS byly rozpoznány odezvy mezi poškozenými a nepoškozenými pneumatickými válci. Rozdíly byly zjištěny porovnáním maximální hodnoty RMS ze snímače upevněného na předním víku válce a snímače upevněného na zadním víku válce pro jeden cyklus. Poškozené a nepoškozené válce byly rozlišeny pomocí rozdílů energetických hodnot přítomných v signálech z obou snímačů v závislosti na zdvihu pístu. Konečné vyhodnocení válce bylo určeno výpočtem celkové hodnoty RMS. Ve třetím kroku experimentu byly válce postupně zatěžovány různými závažími ve svislém směru. Signály akustické emise byly zaznamenány z vysouvání a zasouvání pístu a poté analyzovány. Časové zpoždění se vypočítává z digitálního vstupu a začátku pohybu pístu. Energie signálu a RMS akustické emise porovnávají různé reakce v poškozených a nepoškozených pneumatických válcích s a bez zatížení. Výsledky testu ukázaly lineární vztah mezi křivkou RMS a zatížením. Defekty ovlivňují vztah mezi aplikovaným zatížením a zaznamenaným signálem snímačů.

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