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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.
41

Laboratory Investigation of Quarry Fines for Use in the Construction Industry

Filippidi, Antonia January 2022 (has links)
Quarry fines are by-products of the aggregate extraction and productionprocesses. Because such fine material cannot be marketed, it becomes aburden for the aggregate industry, resulting in stockpiles of financiallyunexploited material. Even though previous research has been focused onminimizing the generation of quarry fines, far too little attention has beenpaid to maximizing their utilization instead. The aim of this thesis is toinvestigate whether 0/2 mm and 0/4 mm quarry fines can be utilized asalternative materials in the construction industry, specifically in theunbound layer of a road or as filling against a bridge. The methodologyconsisted of four laboratory tests that investigated the water content,particle size distribution and percentage of filler content, optimummoisture content (OMC) and maximum dry density (MDD) relationshipas well as bearing capacity of the materials. The results show that theamount of filler content (<0.063 mm) can significantly impact thematerial’s water-holding capacity as well as its compaction capabilities.After comparing the bearing capacity measurements to the technicalrequirements of the Swedish Transport Administration, it was found thatthe 0/2 mm fits the necessary requirements for use in the unbound layerof either a flexible or rigid pavement but not as filling against a bridge.Further research is needed to determine the material’s relationship towater absorption and resistance to freezing and thawing cycles, as it isdifficult to assess its suitability for road construction solely on theseresults; however, despite its limitations, the study provides some valuableinsights into the potential applications of quarry fines.
42

ICHNOLOGY OF THE MARINE K-PG INTERVAL: ENDOBENTHIC RESPONSE TO A LARGE-SCALE ENVIRONMENTAL DISTURBANCE

Wiest, Logan A. January 2014 (has links)
Most major Phanerozoic mass extinctions induced permanent or transient changes in ecological and anatomical characteristics of surviving benthic communities. Many infaunal marine organisms produced distinct suites of biogenic structures in a variety of depositional settings, thereby leaving an ichnological record preceding and following each extinction. This study documents a decrease in burrow size in Thalassinoides-dominated ichnoassemblages across the Cretaceous-Paleogene (K-Pg) boundary in shallow-marine sections along the Atlantic Coastal Plain (Walnridge Farm, Rancocas Creek, and Inversand Quarry, New Jersey) and the Gulf Coastal Plain (Braggs, Alabama and Brazos River and Cottonmouth Creek, Texas). At New Jersey sites, within a regionally extensive ichnoassemblage, Thalassinoides ichnospecies (isp.) burrow diameters (DTh) decrease abruptly by 26-29% (mean K=15.2 mm, mean Pg=11.2 mm; n=1767) at the base of the Main Fossiliferous Layer (MFL) or laterally equivalent horizons. The MFL has been previously interpreted as the K-Pg boundary based on last occurrence of Cretaceous marine reptiles, birds, and ammonites, as well as iridium anomalies and associated shocked quartz. Across the same event boundary at Braggs, Alabama, DTh of simple maze Thalassinoides structures from recurring depositional facies decrease sharply by 22% (mean K=13.1 mm, mean Pg=10.2 mm; n=26). Similarly, at the Cottonmouth Creek site, Texas, Thalassinoides isp. occurring above the previously reported negative £_13C shift and the first occurrence of Danian planktonic foraminifera are 17% smaller in diameter (mean K=21.5 mm, mean Pg=17.9 mm; n=53) than those excavated and filled prior to deposition of a cross-bedded, ejecta-bearing sandstone complex commonly interpreted as the Chicxulub ¡¥event deposit¡¦. At both of these impact-proximal regions, the Cretaceous and Paleogene burrows were preserved in similar lithologies, suggesting that a reduction in size cannot be attributed to sedimentological factors. At all localities, up-section trends in DTh are statistically significant (fÑfnf¬0.05; non-parametric Kruskal-Wallis test). Using the burrow diameter as a proxy for tracemaker body size, a reduction in DTh above the K-Pg boundary likely reflects dwarfing within the post-extinction community of decapod crustaceans. Dwarfing during the early recovery stages of the end-Cretaceous mass extinction, as recorded by ichnofossils, occurred within glauconite-producing (New Jersey), carbonate (Alabama), and siliciclastic (Texas) depositional environments and appears to be widespread. Because this ichnological signal appears to be a general phenomenon across the crisis interval, trace-fossil analysis provides a potential in-situ field method for constraining and correlating the stratigraphic position of the K-Pg and other extinction events, particularly in the absence of other macroscopic, microscopic, and geochemical indicators. Whereas overprinting of the original marine ichnofabric by morphologically similar continental traces is not a concern in lithified sections of Alabama and Texas, such an occurrence must be considered within unconsolidated sections. Within the Hornerstown Formation of New Jersey, a pervasive Thalassinoides framework contains traces of burrowing bees and wasps. Due to their penetration of up to 1 m, excavations just beyond the weathering front are insufficient for exposing the original marine ichnofabric. Insect burrow diameters (7-25 mm) are within the range of Thalassinoides traces (4-31 mm), exhibit occasional branching, and lack of ornamentation (bioglyphs) on the burrow walls. Therefore neither size nor gross morphology are adequate for distinguishing these widely diachronous and unrelated ichnites, especially when the insect burrows have been filled. However, the presence of backfill menisci and a beige clay halo help distinguish the ancient marine burrows, whereas highly oxidized fill and the occurrence of a terminal brooding chamber are diagnostic of modern insect burrows. / Geology
43

Waterworks

Brogren Meijel, Erik January 2023 (has links)
An investigation into the reasons behind the water shortage on Gotland. The project investigated several key factors and proceeded with the design of a surface water treatment plant in one of Gotlands old quarries left behind by the cement industry. The project also investigated and questioned the traditional methods of designing infrastructural buildings through a more architectural lens. The hope was to show a proposal that works but also acts as a pedagogical invitation to learn about where our most important resource comes from.
44

Analysis of the Physiochemical Interactions of Recycled Materials in Concrete

Lowry, Michael Donovan 18 January 2023 (has links)
This thesis broadly addresses the issue of materials sustainability in the production of Portland cement concrete. Two methods are presented, both aimed at achieving more sustainable concrete through the use of waste and recycled materials. The first method involves utilizing reclaimed asphalt pavement (RAP) as an aggregate in structural concrete, and the second method involves utilizing waste quarry fines as partial replacement of Portland cement in concrete mixes. Many efforts have been made in recent years to justify the use of RAP aggregates in concrete. All previous efforts appear to unanimously report a reduction in concrete performance with varying proportions of RAP usage. The poor performance of RAP aggregates in concrete is attributed mainly to a larger, more porous interfacial transition zone (ITZ) and to the cohesive failure of the asphalt. It is hypothesized that the detrimental impact on the ITZ is attributable to organic compounds leached from the asphalt in the high pH pore solution. This study proves the presence of organic compounds in the pore solution and demonstrates that there is an apparent retardation of cement hydration. This study also attempted to pretreat the RAP in a sodium hydroxide (NaOH) solution to pre-leach the organic compounds. The pretreatment demonstrated that organic compounds were leached and that NaOH modified the asphalt surface chemistry. However, only a marginal improvement in compressive strength was observed by completing the pretreatment. Replacement of Portland cement by filler products is a practice aimed at reducing the carbon footprint of concrete, such as is common with Type IL Portland limestone cement. This study investigates the impact of replacing cement with seven different quarry fines materials. The quarry fines were used to replace cement at 5% to 20% by volume in either cement paste or mortar samples that were then analyzed for various physicochemical properties. It was found that all the quarry fines had detrimental impact on the hydration kinetics of cement pastes. The inclusion of quarry fines was also found to cause varying degrees of reduction in mortar compressive strength. While further analyses of the quarry fines are required, quarry fines 2, 5 and 7 did display encouraging signs to suggest the potential for use as a filler material in blended cements. / Master of Science / This thesis broadly addresses the issue of sustainability in the cement and concrete industry. Sustainability is a significant problem for the cement and concrete industry due to the large amount of carbon emissions produced in the manufacturing process of Portland cement. One method to reduce the carbon footprint of concrete is to use recycled aggregates, and reclaimed asphalt pavement (RAP) is investigated in this thesis as a recycled aggregate option. Previous studies have shown that the use of RAP in concrete results in poor mechanical performance when compared to conventional concrete. In this thesis, the RAP was pretreated by soaking it in sodium hydroxide (NaOH) to see if any improvement is noted. It was determined that the pretreatment resulted in marginal improvements in concrete performance. Another method to reduce the carbon footprint of concrete is through the use of substitutions of Portland cement. In this thesis, quarry fines from around Virginia were investigated for potential as substitutive material. Quarry fines are a by-product from quarrying operations and are often considered a waste material because they have limited applications. This study analyzed the performance of cementitious materials prepared with various substitutive percentages of quarry fines and found that, in general, the inclusion of quarry fines resulted in a decrease of mechanical performance. In total, seven quarry fines were tested and only two showed potential for use as a substitution in Portland cement concrete. These two investigations are essential in reaching the goal of reducing the carbon footprint of the cement and concrete industry.
45

Clovis Lithic Debitage from Excavation Area 8 at the Gault Site (41BL323), Texas: Form and Function

Pevny, Charlotte D. 2009 May 1900 (has links)
This dissertation focuses on two portions of the Clovis lithic assemblage recovered from Excavation Area 8 at the Gault site (41BL323) located in central Texas. Gault is a quarry-camp visited by hunter-gatherer groups for at least 13,000 years, with Paleoindian, Archaic, and Late Prehistoric occupations. Freshwater seep springs, a diverse array of floral and faunal resources, and an abundant outcrop of high-quality toolstone at the site created an ideal location for people who lived a mobile hunting-andgathering way of life. The site is currently the only locale with two stratigraphically separate Clovis components-a lower geologic unit designated 3a and an upper unit designated 3b. Both are represented in Excavation Area 8 where, in the spring of 2000, Texas A&M University (TAMU) excavated 22 1-m2 contiguous units. For this research, 3375 complete flakes were analyzed individually to characterize Clovis debitage as represented at Excavation Area 8 and to establish if there are technological differences between the debitage assemblages recovered from Units 3a and 3b. The two Clovis components are quite similar from a technological standpoint. Minor differences appear to be related to site formation processes and intensity of site use. The second objective was to determine if Clovis debitage has diagnostic technological traits that allow confident assignment to the Clovis era. To test whether Clovis debitage is distinctive, it was compared to debitage recovered from later cultural components at the site. No evidence of a true blade technology was observed in the post- Clovis Paleoindian or Early Archaic debitage assemblages, although biface manufacture continued through time. Technologically, few differences were observed between the Clovis, post-Clovis Paleoindian, and Early Archaic debitage related to biface reduction. While overshot flakes may be diagnostic of Clovis biface technology, biface thinning flakes and other non-distinctive debitage showed few differences between components. During debitage analysis pieces were selected in an attempt to identify edgemodified tools. Low- and high-power usewear analysis was employed to make determinations concerning the cultural modification or use of flakes. This study concluded post-depositional damage affected most of the collection and there was minimal usewear-or minimal observable usewear-on flakes. Taphonomic processes interfered to a great extent with drawing firm inferences on tool use and possibly hindered the identification of tools. Of the 3375 pieces of Clovis debitage originally analyzed, 26 specimens were classified as tools based mainly on invasive, patterned flaking with less reliance on microscopic use indicators. Of these, inference of use was assigned to nine tools.
46

Performing arts centre at Quarry Bay

Ngan, Chiu-long, Sunny., 顔昭朗. January 2002 (has links)
published_or_final_version / Architecture / Master / Master of Architecture
47

Banais como pedra : as reflexões sobre natureza e meio ambiente de habitantes do entorno de uma pedreira em Porto Alegre (RS)

Bexiga, Stéphanie Ferreira January 2013 (has links)
Sob as regras da economia mineral, as pedreiras situam-se não tão próximas das zonas urbanas, mas também não muito distantes. Em Porto Alegre, capital do Rio Grande do Sul (Brasil), uma pedreira localizada num bairro da zona leste configura o que, para alguns habitantes, não é parte da cidade, embora situada em seus limites político-administrativos. A vila das Pedreiras (uma das nomenclaturas utilizadas pela prefeitura municipal) é habitada por famílias de trabalhadores e ex-trabalhadores de uma empresa mineradora, que realiza a extração de rochas no local, bem como por outros habitantes que encontraram no local uma forma acessível de aquisição de moradia. A partir da etnografia realizada num lugar onde, há quatro décadas, é extraído esse material “essencial à cidade”, interroga-se sobre como os habitantes concebem sua relação com a pedreira e a cidade desde o ponto de vista daqueles que são atingidos diariamente pela convivência com a extração de rochas. É desde esse cotidiano que busca-se conhecer as diferentes formas de uso, significação e apropriação da “natureza”, esta sendo termo de disputa tanto material quanto simbólica entre os sujeitos que habitam um lugar atravessado pela “injustiça ambiental” própria dos territórios onde a mineração se instala. Nesta dissertação objetiva-se revelar as perspectivas locais de populações que, na periferia de uma cidade, oferecem concepções outras (alternativas) sobre meio ambiente e natureza, denunciando as práticas das retóricas desenvolvimentistas. / Under the rules of the mineral economy, the quarries are located not so close to urban areas, but also not too far away. In Porto Alegre, capital of Rio Grande do Sul (Brazil), a quarry located in the east side neighborhood sets which is not part of the city, for some people, although situated in their political-administrative boundaries. The village of Quarries (one of the nomenclatures used by city hall) is inhabited by families of workers and former workers of a mining company, which performs the extraction of rocks at the site, as well as other inhabitants they found in place an affordable way to acquisition of property. From the ethnography in a place where, during four decades, this "essential to the city"material is extracted, wonders about the people conceive their relationship with the quarry and the city from the point of view of those who are affected daily by the coexistence with the extraction of rocks. It is from this routine that seeks to identify the different forms of use, appropriation and meanings of "nature", this term being both material and symbolic struggle between the subjects who inhabit a place traversed by the very "environmental injustice" of territories where mining settles. In this thesis we aim to reveal the perspectives of local populations on the outskirts of a city, offer other concepts (alternatives) for the environment and nature, denouncing the practices of developmental rhetoric.
48

Banais como pedra : as reflexões sobre natureza e meio ambiente de habitantes do entorno de uma pedreira em Porto Alegre (RS)

Bexiga, Stéphanie Ferreira January 2013 (has links)
Sob as regras da economia mineral, as pedreiras situam-se não tão próximas das zonas urbanas, mas também não muito distantes. Em Porto Alegre, capital do Rio Grande do Sul (Brasil), uma pedreira localizada num bairro da zona leste configura o que, para alguns habitantes, não é parte da cidade, embora situada em seus limites político-administrativos. A vila das Pedreiras (uma das nomenclaturas utilizadas pela prefeitura municipal) é habitada por famílias de trabalhadores e ex-trabalhadores de uma empresa mineradora, que realiza a extração de rochas no local, bem como por outros habitantes que encontraram no local uma forma acessível de aquisição de moradia. A partir da etnografia realizada num lugar onde, há quatro décadas, é extraído esse material “essencial à cidade”, interroga-se sobre como os habitantes concebem sua relação com a pedreira e a cidade desde o ponto de vista daqueles que são atingidos diariamente pela convivência com a extração de rochas. É desde esse cotidiano que busca-se conhecer as diferentes formas de uso, significação e apropriação da “natureza”, esta sendo termo de disputa tanto material quanto simbólica entre os sujeitos que habitam um lugar atravessado pela “injustiça ambiental” própria dos territórios onde a mineração se instala. Nesta dissertação objetiva-se revelar as perspectivas locais de populações que, na periferia de uma cidade, oferecem concepções outras (alternativas) sobre meio ambiente e natureza, denunciando as práticas das retóricas desenvolvimentistas. / Under the rules of the mineral economy, the quarries are located not so close to urban areas, but also not too far away. In Porto Alegre, capital of Rio Grande do Sul (Brazil), a quarry located in the east side neighborhood sets which is not part of the city, for some people, although situated in their political-administrative boundaries. The village of Quarries (one of the nomenclatures used by city hall) is inhabited by families of workers and former workers of a mining company, which performs the extraction of rocks at the site, as well as other inhabitants they found in place an affordable way to acquisition of property. From the ethnography in a place where, during four decades, this "essential to the city"material is extracted, wonders about the people conceive their relationship with the quarry and the city from the point of view of those who are affected daily by the coexistence with the extraction of rocks. It is from this routine that seeks to identify the different forms of use, appropriation and meanings of "nature", this term being both material and symbolic struggle between the subjects who inhabit a place traversed by the very "environmental injustice" of territories where mining settles. In this thesis we aim to reveal the perspectives of local populations on the outskirts of a city, offer other concepts (alternatives) for the environment and nature, denouncing the practices of developmental rhetoric.
49

Banais como pedra : as reflexões sobre natureza e meio ambiente de habitantes do entorno de uma pedreira em Porto Alegre (RS)

Bexiga, Stéphanie Ferreira January 2013 (has links)
Sob as regras da economia mineral, as pedreiras situam-se não tão próximas das zonas urbanas, mas também não muito distantes. Em Porto Alegre, capital do Rio Grande do Sul (Brasil), uma pedreira localizada num bairro da zona leste configura o que, para alguns habitantes, não é parte da cidade, embora situada em seus limites político-administrativos. A vila das Pedreiras (uma das nomenclaturas utilizadas pela prefeitura municipal) é habitada por famílias de trabalhadores e ex-trabalhadores de uma empresa mineradora, que realiza a extração de rochas no local, bem como por outros habitantes que encontraram no local uma forma acessível de aquisição de moradia. A partir da etnografia realizada num lugar onde, há quatro décadas, é extraído esse material “essencial à cidade”, interroga-se sobre como os habitantes concebem sua relação com a pedreira e a cidade desde o ponto de vista daqueles que são atingidos diariamente pela convivência com a extração de rochas. É desde esse cotidiano que busca-se conhecer as diferentes formas de uso, significação e apropriação da “natureza”, esta sendo termo de disputa tanto material quanto simbólica entre os sujeitos que habitam um lugar atravessado pela “injustiça ambiental” própria dos territórios onde a mineração se instala. Nesta dissertação objetiva-se revelar as perspectivas locais de populações que, na periferia de uma cidade, oferecem concepções outras (alternativas) sobre meio ambiente e natureza, denunciando as práticas das retóricas desenvolvimentistas. / Under the rules of the mineral economy, the quarries are located not so close to urban areas, but also not too far away. In Porto Alegre, capital of Rio Grande do Sul (Brazil), a quarry located in the east side neighborhood sets which is not part of the city, for some people, although situated in their political-administrative boundaries. The village of Quarries (one of the nomenclatures used by city hall) is inhabited by families of workers and former workers of a mining company, which performs the extraction of rocks at the site, as well as other inhabitants they found in place an affordable way to acquisition of property. From the ethnography in a place where, during four decades, this "essential to the city"material is extracted, wonders about the people conceive their relationship with the quarry and the city from the point of view of those who are affected daily by the coexistence with the extraction of rocks. It is from this routine that seeks to identify the different forms of use, appropriation and meanings of "nature", this term being both material and symbolic struggle between the subjects who inhabit a place traversed by the very "environmental injustice" of territories where mining settles. In this thesis we aim to reveal the perspectives of local populations on the outskirts of a city, offer other concepts (alternatives) for the environment and nature, denouncing the practices of developmental rhetoric.
50

Devenir des floculants à base de polyacrylamide dans un site de granulat : interactions avec les solides naturels et photodégradation / The fate of polyacrylamide based floculants in aggregate quarry : interactions with natural solids and photodegradation

Mnif, Ines 03 July 2015 (has links)
Les floculants à base de polyacrylamide (PAM) sont produits à partir du monomère toxique : l’acrylamide (AMD) et peuvent en contenir des quantités résiduelles (jusqu’à 0,1% en Europe). Après utilisation pour faciliter la séparation solide/liquide des eaux de procédés dans les industries de granulat, ces floculants sont stockés avec les boues de décantation dans des lagunes à partir desquelles une dissémination de l’AMD et du PAM vers les eaux de surface ou les eaux souterraines peut avoir lieu. Dans ces travaux de thèse, les interactions du PAM et de l’AMD avec des particules de boue et des phases argileuses (kaolinite et illite, utilisées pour étanchéifier les lagunes de décantation) ont été étudiées. Pour pouvoir quantifier correctement l’AMD, une méthode d’analyse basée sur la HPLC/MS/MS en injection directe a été développée. Cette méthode a été validée avec les normes Afnor NF T 90-210 et NF T 90-220 avec une limite de quantification égale à 1 µg/L. L’étude de l’interaction de l’AMD avec des particules de boue d’un site de granulat et deux argiles (kaolinite et illite) a mis en évidence une faible adsorption de l’AMD sur ces phases solides (<10%), indépendante du temps, de la concentration en AMD et du pH. Inversement, le PAM s’adsorbe fortement et irréversiblement sur la boue, la kaolinite et l’illite avec une cinétique rapide de 1er ordre. Les isothermes d’adsorption sont bien corrélées avec les modèles de Langmuir et de Freundlich. Les quantités d’adsorption du PAM sont indépendantes du pH des suspensions mais fortement impactées par la force ionique qui influence les interactions électrostatiques entre le PAM et les surfaces solides. / Polyacrylamide (PAM) based floculants are produced from the highly toxic acrylamide (AMD) monomer and can contain residual amounts (up to 0.1% in Europe) of AMD. After they are used to facilitate liquid/solid separation of process water in aggregate quarries, PAM floculants are stored, with the sewage sludge, in decantation lagoons. Dissemination of AMD and PAM to groundwater and surface water from these lagoons can occur. In this work, we aimed to study the interactions of AMD and PAM with sludge particles and clays (kaolinite and illite used for decantation lagoon sealing) from aggregate quarry. To correctly quantify the AMD, analytical method based on HPLC/MS/MS with direct injection was developed. This method was validated according to the Afnor guidelines (NF T 90-210 and NF T 90-220) with a limit of quantification of 1 µg/L. Results of AMD adsorption experiments showed a low adsorption of AMD to sludge and clay (kaolinite and illite) particles, which is independent of time, AMD concentration and pH. Inversely, PAM was found to adsorb strongly and irreversibly to sludge, kaolinite and illite with a rapid kinetic of adsorption which consists of first order kinetic. Adsorption isotherms are well correlated with Langmuir and Freundlich models. PAM adsorption quantities are independent on the pH of suspensions, but are strongly impacted by the ionic strength which affects electrostatic interactions between PAM and solid surfaces.

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