• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 38
  • 9
  • 7
  • 7
  • 5
  • 3
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 91
  • 13
  • 12
  • 10
  • 10
  • 9
  • 9
  • 8
  • 8
  • 7
  • 7
  • 6
  • 5
  • 5
  • 5
  • 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.
71

Land Use and Landsliding in Price Hill, Cincinnati, Ohio

Agnello, Tim Joseph 22 May 2002 (has links)
No description available.
72

Characterization of Quarry By-Products as a Partial Replacement of Cement in Cementitious Composites

Nguyen, Tu-Nam N. 21 August 2023 (has links)
Concrete is the most widely used man-made material in the world. Its versatility, strength, and relative ease of construction allow it to be used in the majority of civil infrastructure. However, concrete production plays a significant role in greenhouse gas emissions, accounting for around 8% of CO2 emissions worldwide. This thesis aims to reduce the demand for cement in concrete construction, thus reducing the carbon footprint of the concrete, by focusing on classifying and determining the effectiveness of seven different quarry by-products as partial replacements of cement. Several methods were utilized in this study to characterize the quarry by-products: particle size distribution, helium pycnometry, X-Ray diffraction, X-Ray fluorescence, scanning electron microscopy, and a modified ASTM C1897 Method A that utilizes isothermal calorimetry and thermogravimetric analysis. These various methods allowed for the determination of the physical properties (e.g., gradation, specific gravity, and morphology) and the chemical properties (e.g., mineralogy and reactivity in a cementitious system). The quarry by-products were classified as four granites, two limestones, and one greenstone. These quarry by-products were found to be non-pozzolanic and non-hydraulic. However, there are indications that there may be reactions with the various clays and feldspars in the quarry by-products with calcium hydroxide, which suggests a degree of reactivity that is not necessarily pozzolanic or hydraulic. / Master of Science / Concrete is the most widely used man-made material in the world. Its versatility, strength, and relative ease of construction allow it to be used in the majority of civil infrastructure. However, concrete production plays a significant role in greenhouse gas emissions, accounting for around 8% of CO2 emissions worldwide. This thesis aims to reduce the demand for cement in concrete construction, thus reducing the carbon footprint of the concrete, by focusing on classifying and determining the effectiveness of seven different quarry by-products as partial replacements of cement. Several methods were utilized in this study to determine the physical properties (e.g., gradation, specific gravity, and morphology) and the chemical properties (e.g., mineralogy and reactivity in a cementitious solution) of the materials. The quarry by-products were classified as four granites, two limestones, and one greenstone. In general, these quarry by-products were not found to be reactive as a supplementary cementitious material, although the data may suggest some degree of reactivity between calcium hydroxide and the clays and/or feldspars in the quarry by-products.
73

Om stenar kunde tala : arkeologiska rön och bebyggelsehistorisk kontext av kvarnstensbrottet Östra Utsjö i Malung / If stones could speak : the history and archaeology of the millstone quarry of Eastern Utsjö in Malung, province of Dalarna, Sweden

Mellquist Danielson, Bente January 2011 (has links)
This paper deals with village history around millstone quarry Eastern Utsjö in Malung, Sweden, in the hope of finding deposits that could date the quarry, in that the quarry in the current situation is dated only by the millstone fragments outside the resort. My purpose was to conduct a discussion on the quarry alone can be dated by deposits outside the resort. I have used FMIS RAÄ:s fornsök and a lot of literature to identify village history. The results showed that it is not possible to date the millstone quarry from village history, but through deposits outside the resort of Malung, which have been found around Mälardalen, Sweden through archaeological excavations, and derived from the millstone quarry Eastern Utsjö, can put an age on the quarry.
74

Koldioxidreducering av en bergtäkts fordonsflotta / Carbon dioxide reduction of a quarry vehicle fleet

Myhrberg, Jakob, Raab-Obermayr, Gustav January 2019 (has links)
Ballast som byggnadsmaterial är viktigt för att utveckla vårt samhälle då det bland annat används som beståndsdel i asfalt och betong. Det är därför viktigt att bergkross som bryts i bergtäkter har en fungerande produktion för att möta efterfrågan men också för att Sverige ska kunna nå målet att vara klimatneutralt 2045. Syftet med arbetet är att minska miljöpåverkan i en bergtäkt från de interna transporterna och målet är att ta fram åtgärder för att uppnå detta. De metoder som har använts är litteraturstudier, beräkningar, simuleringar och intervjuer. Genom beräkningarna kunde ett resultat i detta arbete visa att en reducering med 88 % av koldioxidutsläpp kan göras genom att använda biodrivmedlet HVO Diesel 100. Det har med hjälp av intervjuer och litteraturstudier dessutom dragits en slutsats att framtidens bergtäkter antas producera bergkross med elektriska autonoma maskiner. / Ballast as a building material is important for developing our society as it’s used as a component in asphalt and concrete. Hence it is important that crushed rock extracted from a quarry have a functioning production to meet the demand that exists, but also because Sweden should be able to reach the goal of being climate neutral 2045. The purpose of this study is to reduce the environmental impact in a quarry from the internal transports and the aim is to bring out suggestions to achieve this. The methods that have been used are literature studies, calculations, simulations and interviews. Through the calculations, a result in this work showed that a reduction of 88 % of carbon dioxide emissions can be made by using the biofuel HVO Diesel 100. In addition, with the help of interviews and literature studies, conclusions have been drawn that the future quarries are believed to produce crushed rock with electric autonomous machines.
75

Explorative Multivariate Data Analysis of the Klinthagen Limestone Quarry Data / Utforskande multivariat analys av Klinthagentäktens projekteringsdata

Bergfors, Linus January 2010 (has links)
<p> </p><p>The today quarry planning at Klinthagen is rough, which provides an opportunity to introduce new exciting methods to improve the quarry gain and efficiency. Nordkalk AB, active at Klinthagen, wishes to start a new quarry at a nearby location. To exploit future quarries in an efficient manner and ensure production quality, multivariate statistics may help gather important information.</p><p>In this thesis the possibilities of the multivariate statistical approaches of Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression were evaluated on the Klinthagen bore data. PCA data were spatially interpolated by Kriging, which also was evaluated and compared to IDW interpolation.</p><p>Principal component analysis supplied an overview of the variables relations, but also visualised the problems involved when linking geophysical data to geochemical data and the inaccuracy introduced by lacking data quality.</p><p>The PLS regression further emphasised the geochemical-geophysical problems, but also showed good precision when applied to strictly geochemical data.</p><p>Spatial interpolation by Kriging did not result in significantly better approximations than the less complex control interpolation by IDW.</p><p>In order to improve the information content of the data when modelled by PCA, a more discrete sampling method would be advisable. The data quality may cause trouble, though with sample technique of today it was considered to be of less consequence.</p><p>Faced with a single geophysical component to be predicted from chemical variables further geophysical data need to complement existing data to achieve satisfying PLS models.</p><p>The stratified rock composure caused trouble when spatially interpolated. Further investigations should be performed to develop more suitable interpolation techniques.</p>
76

Explorative Multivariate Data Analysis of the Klinthagen Limestone Quarry Data / Utforskande multivariat analys av Klinthagentäktens projekteringsdata

Bergfors, Linus January 2010 (has links)
The today quarry planning at Klinthagen is rough, which provides an opportunity to introduce new exciting methods to improve the quarry gain and efficiency. Nordkalk AB, active at Klinthagen, wishes to start a new quarry at a nearby location. To exploit future quarries in an efficient manner and ensure production quality, multivariate statistics may help gather important information. In this thesis the possibilities of the multivariate statistical approaches of Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression were evaluated on the Klinthagen bore data. PCA data were spatially interpolated by Kriging, which also was evaluated and compared to IDW interpolation. Principal component analysis supplied an overview of the variables relations, but also visualised the problems involved when linking geophysical data to geochemical data and the inaccuracy introduced by lacking data quality. The PLS regression further emphasised the geochemical-geophysical problems, but also showed good precision when applied to strictly geochemical data. Spatial interpolation by Kriging did not result in significantly better approximations than the less complex control interpolation by IDW. In order to improve the information content of the data when modelled by PCA, a more discrete sampling method would be advisable. The data quality may cause trouble, though with sample technique of today it was considered to be of less consequence. Faced with a single geophysical component to be predicted from chemical variables further geophysical data need to complement existing data to achieve satisfying PLS models. The stratified rock composure caused trouble when spatially interpolated. Further investigations should be performed to develop more suitable interpolation techniques.
77

Étude technologique et morphologique de la cornéenne dans le sud du Québec : le cas de la carrière préhistorique du mont Royal (BjFj-97) à Montréal.

Bélanger, Jonathan 08 1900 (has links)
Le site de la carrière du mont Royal (BjFj-97), découvert en 1993 par Yvon Codère et inventorié en 1997 par l’équipe d’Ethnoscop Inc., constitue une énigme archéologique intéressante pour quiconque s’intéresse à la préhistoire de l’île de Montréal et de sa région adjacente. Lors des activités archéologiques de 1997, quelques idées furent émises quant à son affiliation chronologique et sa nature, suggérant une occupation remontant à l’Archaïque terminal (4000 à 3000 AA) orientée vers l’extraction et la transformation de la cornéenne, une pierre métamorphique résultant de la transformation du substrat rocheux en place suite à des intrusions magmatiques lors du Crétacé qui ont créé les Montérégiennes. Le matériel, comprenant plus de 10 000 déchets de taille et un peu plus de 70 artéfacts divers, ne fît pas l’objet d’analyses poussées hormis la datation approximative du site par un examen sommaire des pointes de projectile. Ce mémoire reprend les données de 1997 et apporte une perspective nouvelle au site en décrivant morphologiquement et technologiquement le débitage de la pierre de façon à comprendre la chaîne opératoire de la cornéenne, une matière peu étudiée, mais fort commune au Québec méridional, appréhender les possibilités de la matière et aborder les questions de datation. L’ensemble du matériel lithique fît l’objet d’une analyse lithique poussée axée sur le débitage et les produits finis et propose la prépondérance de la taille bifaciale, ponctuée par un débitage sur éclat conséquent. L’ensemble des étapes de la chaîne opératoire est présent sur le site de la carrière du mont Royal. La cornéenne est une matière difficile à tailler en raison de son imprévisibilité, liée à la structure même de la matière, menant à un fort taux d’échecs lors de l’élaboration des outils. La datation de l’occupation principale du site pointe vers l’Archaïque terminal, mais le caractère équivoque des diverses classes d’objets rend difficile sa définition absolue, faute d’objets parfaitement diagnostiques. Le site BjFj-97 ressemble grandement à un site homologue en Nouvelle-Angleterre où la cornéenne fût travaillée suivant le même schéma opératoire, suggérant un apparentement culturel possible. La cornéenne abonde et domine dans les assemblages archéologiques de la région montréalaise, substituant ainsi des matières de meilleure qualité absentes régionalement. Leurs correspondances chronologiques transcendent celles établies lors de l’analyse du matériel de la carrière et montrent un étalement chronologiquement plus étendu, de l’Archaïque laurentien au Sylvicole supérieur. La cornéenne se retrouve habituellement sous forme d’outils bifaciaux fonctionnels (bifaces, couteaux et pointes de projectile) de piètre facture et d’outils sur éclats (grattoirs et racloirs) rudimentaires, suggérant une signification strictement utilitaire, le propre des matières de basse qualité. Les modes d’extraction de la cornéenne restent inconnus sur le mont Royal. Le mont Royal est plus qu’un vulgaire point défensif, il constitue la base de la subsistance des populations préhistoriques de jadis où se trouvent les matériaux nécessaires à la taille d’outils de prédation liés à un mode de vie mobile où domine la chasse. / The Mount Royal quarry site (BjFj-97), discovered in 1993 by Yvon Codère and test pitted in 1997 by Ethnoscop Inc., is an interesting archaeological puzzle for anyone interested in the Montreal region prehistory. Following the 1997 archaeological testing, some ideas were raised about the quarry’s cultural affiliation and its chronological position. Archaeologists proposed a primary occupation focused on hornfels extraction and transformation dating back to the Terminal Archaic period (4000-3000 BP). Hornfels is a metamorphic rock that resulted from bedrock being “cooked” during cretaceous magmatic intrusion that created the Monteregian hills. The material recovered, includes more than 10,000 flakes and over 70 artefacts, and is analysed here for the first time. This thesis provides a new perspective on the Mount Royal quarry site describing morphologically and technologically the stone tool production in order to better understand the hornfels’ chaîne opératoire. This lithic material is common on archaeological sites in southern Quebec can help us to address some issues of dating the quarry site. The entire lithic collection was subjected to an extensive analysis including all of the debitage and finished products, and shows the dominance of bifacial flintknapping, with some flake tools also being produced. All stages f the lithic reduction sequence are present on the Mount Royal quarry site. Hornfels is a difficult material to work because of its unpredictability, due to structure of matter, leading to a high rate of failures in the manufacture of tools. The main occupation of the site is dated to the Terminal Archaic, but the equivocal nature of the various objects makes it difficult to clearly define the period of occupation and exploitation. Site BjFj-97 is similar to another site in New England where hornfels was worked using a similar lithic reduction sequence, suggesting a possible cultural kinship. Hornfels is common on sites in the Montreal area, often substituting for better materials. The presence of hornfels on these sites suggests a wider chronological spread than that established from the material analysis from the quarry and covers the Laurentian Archaic to Woodland periods. Hornfels is usually found in formal bifacial tool forms (bifaces, knives and projectile points) and less formal flakes tools (scrapers) suggesting a strictly utilitarian significance, characteristic of low quality materials. Little is known about hornfels extraction methods on the mountain. Mount Royal is more than a defensive point: it forms the basis of the livelihood of the prehistoric people where predation tools were associated with a mobile lifestyle dominated by hunting.
78

Étude technologique et morphologique de la cornéenne dans le sud du Québec : le cas de la carrière préhistorique du mont Royal (BjFj-97) à Montréal

Bélanger, Jonathan 08 1900 (has links)
No description available.
79

INFLUÊNCIA DE ADIÇÕES MINERAIS POZOLÂNICAS E DE FINOS DE PEDREIRA NAS PROPRIEDADES MECÂNICAS E NA MICROESTRUTURA DO CONCRETO AUTO-ADENSÁVEL / Influence of the mineral additions and the quarry dust in the mechanical properties and the microstructure of the self-compacting concrete

ARAÚJO, Janaína das Graças 27 August 2007 (has links)
Made available in DSpace on 2014-07-29T15:03:38Z (GMT). No. of bitstreams: 1 dissertacao janaina parte 1.pdf: 4357572 bytes, checksum: 40dbbd6f2f4cdbb3296717b82f972c80 (MD5) Previous issue date: 2007-08-27 / For the benefits of its properties in fresh state, self-compacting concrete (SCC) demands a high powder content in the composition, nearby 450kg/m³. The quarry dust, resultant material of the coarse aggregate production, can b considered as an economic and sustainable alternative for the development of the SCC. As well as the quarry dust, mineral additions, is used in conventional concretes and can also be used in the self-compacting concrete, with the same kind of benefits. Using the mix design for SCC developed by Tutikian (2004) a study for evaluation of the SCC mechanical properties were done, where natural sand had been partially replaced by quarry micaschist, granite and gneiss - and cement for silica fume, metakaolin and calcined clay pozolan. The test methods for fresh state used was Slump-flow (FURNAS, 2005a), U-Box (FURNAS, 2005b), Entrained air (NM 47, 2002) and Specific gravity (9833, 1997). Cylindrical test specimen 100x200 mm had been molded for tests - compressive strength (NBR 5739, 1994), modulus of elasticity (NBR 8522, 1984), splitting tensile strength (NBR 7222, 1994) and flexural strength (NBR 12142, 1991) -the age of 28 days. Samples using the mixture1: 4,5 had been analyzed by scanning electron microscope (SEM). The results show that it can be possible the use of different additions for the production of high quality SCC. We detach the small variability of the specific gravity, as well as the entrained air, wide presented low values. For concretes with same compressive strength, the values of modulus of elasticity had varied between 5 and 60% and the splitting tensile strength and flexural strength had been remained between 10 and 15% / Para atender suas propriedades no estado fresco, o concreto autoadensável (CAA) demanda uma grande quantidade de finos em sua composição, em média 450 kg/m³. Os finos de pedreira, material resultante do processo de britagem, surgem como alternativa econômica e sustentável no desenvolvimento do CAA. Além dos finos, adições minerais pozolânicas, muito utilizadas em concretos convencionais, podem ser utilizadas também no concreto auto-adensável, com os mesmos benefícios. Utilizando-se o método de dosagem para CAA proposto por Tutikian (2004), foi desenvolvido um estudo para avaliação das propriedades mecânicas do CAA, onde foram realizadas substituições parciais da areia natural por finos de pedreira micaxisto, granito e gnaisse e substituições parciais de cimento por sílica ativa, metacaulim e pozolana de argila calcinada. Os ensaios no estado fresco realizados foram Espalhamento (FURNAS, 2005a), Caixa U (FURNAS, 2005b), Teor de Ar (NM 47, 2002) e Massa Específica (NBR 9833, 1997). Corpos-de-prova cilíndricos com dimensões de 100x200 mm foram moldados para ensaios no estado endurecido resistência à compressão (NBR 5739, 1994), módulo de elasticidade (NBR 8522, 1984), tração por compressão diametral (NBR 7222, 1994) e tração na flexão (NBR 12142, 1991) na idade de 28 dias. Foram analisadas amostras das composições intermediárias (1:4,5) em microscópio eletrônico de varredura (MEV). Os resultados obtidos mostram ser possível a utilização de diferentes adições na produção de CAA s de qualidade. Destaca-se a pouca variabilidade das massas específicas, bem como dos teores de ar, que apresentaram valores baixos. Para concretos de mesma resistência à compressão, os valores obtidos para o módulo de elasticidade variaram entre 5 e 60% e as resistências à tração mantiveram-se entre 10 e 15%
80

Real-Time Visualization of Construction Equipment Performance / Realtidsvisualisering av materialhantering på bergtäckt

Palomeque, Carlos January 2014 (has links)
This thesis is a proof-of-concept project that aims at modify and reuse existing communication protocols of wireless vehicle to vehicle communication in order to build a prototype of a real time graphical application that runs in an embedded environment. The application is a 2D visualization of the flow of material at a quarry and is built on top of existing communication protocols that enable wireless vehicle to vehicle communication according to the 802.11p standard for intelligent transport solutions. These communication protocols have already been used within the Volvo group in other research rojects, but not in a context of a real-time graphical 2D visualization. The application runs on an ALIX embedded motherboard and combined with the necessary hardware represent one node that makes the communication network. The visualization monitors the position of every active node in the network and the flow of material between material locations and crusher that process the material at the quarry. The visualization is implemented in C/C++ using Qt 4.6.2 Graphics View framework.

Page generated in 0.0704 seconds