• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 256
  • 33
  • 25
  • 19
  • 17
  • 17
  • 12
  • 10
  • 4
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 491
  • 87
  • 81
  • 53
  • 42
  • 38
  • 38
  • 36
  • 33
  • 31
  • 29
  • 29
  • 28
  • 28
  • 27
  • 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.
311

MODELING AND OPTIMIZATION OF CRUDE OIL DESALTING

Ilkhaani, Shahrokh 06 November 2014 (has links)
When first received by a refinery, the crude oil usually contains some water, mineral salts, and sediments. The salt appears in different forms, most often times it is dissolved in the formation water that comes with the crude i.e. in brine form, but it could also be present as solid crystals, water-insoluble particles of corrosion products or scale and metal-organic compounds such as prophyrins and naphthenates. The amount of salt in the crude can vary typically between 5 to 200 PTB depending on the crude source, API, viscosity and other properties of the crude. For the following reasons, it is of utmost importance to reduce the amount of salt in the crude before processing the crude in the Crude Distillation Unit and consequently downstream processing units of a refinery. 1. Salt causes corrosion in the equipment. 2. Salt fouls inside the equipment. The fouling problem not only negatively impacts the heat transfer rates in the exchangers and furnace tubes but also affects the hydraulics of the system by increasing the pressure drops and hence requiring more pumping power to the system. Salt also plugs the fractionator trays and causes reduced mass transfer i.e. reduced separation efficiency and therefore need for increased re-boiler/condenser duties. 3. The salt in the crude usually has a source of metallic compounds, which could cause poisoning of catalyst in hydrotreating and other refinery units. Until a few years ago, salt concentrations as high as 10 PTB (1 PTB = 1 lb salt per 1000 bbl crude) was acceptable for desalted crude; However, most of the refineries have adopted more stringent measures for salt content and recent specs only allow 1 PTB in the desalted crude. This would require many existing refineries to improve their desalting units to achieve the tighter salt spec. This study will focus on optimizing the salt removal efficiency of a desalting unit which currently has an existing single-stage desalter. By adding a second stage desalter, the required salt spec in the desalted crude will be met. Also, focus will be on improving the heat integration of the desalting process, and optimization of the desalting temperature to achieve the best operating conditions in the plant after revamp.
312

Good Men Grow Corn: Embodied Ecological Heritage and Health in a Belizean Mopan Community

Baines, Kristina Linda 01 January 2012 (has links)
Recent developments in land rights and land use in the Toledo district, Belize has generated anthropological and activist interest surrounding traditional ecological knowledge and practice, and the role of heritage in communities. This study explores the connection between ecological knowledge and practices, and the concurrent construction of heritage, and community health and wellness, broadly defined. Developing and using the concept of "embodied ecological heritage," this dissertation takes a phenomenological approach to understanding the convergence of ecological heritage and health in multiple realms of everyday life, arguing that lived experience of participating in "traditional" practices is fundamentally connected to wellness in the Mopan community of Santa Cruz. Using the results of ethnographic research using multiple methodologies across 76 households over a period of 11 months, this dissertation presents a detailed account of how Mopan Maya participants view ecological skill and knowledge as critical to being and living well, arguing that social factors, such as work and food choices, have an effect on wellness. The research contributes to a growing number of studies linking changes in the body and overall health status to everyday practices within communities. Outlining how certain knowledge and particular practices, such as exchanging labor and making baskets, become prioritized as heritage through both their conceptualization and deployment, the analysis centers on individual bodies as the foci of skill, sensory experience and change. The timely nature of making these connections explicit is discussed in light of ongoing "development" in Maya communities and beyond, with an illumination of how changing land use patterns have far-reaching effects on wellness from multiple perspectives; individual, social, ecological and political, and concluding that a consideration of wellness can benefit from looking at the processes involved in heritage construction as it relates to ecological practice.
313

A Paleoethnobotanical Perspective on Late Classic Maya Cave Ritual at the Site of Pacbitun, Belize

Parker, Megan 12 August 2014 (has links)
This thesis presents the results of paleoethnobotanical investigations conducted at nine karst sites associated with the Maya site of Pacbitun in western Belize. The archaeobotanical remains were deposited during the Late Classic period and the site was abandoned at some point during this same time (c. A.D. 900). Paleoenvironmental data from the Maya Lowlands indicates that human activity contributed to regional climate change during the Late/Terminal Classic period. However, site-specific research has demonstrated a variety of responses to these social and ecological changes. The archaeobotanical data from this study is used as a proxy for understanding how people at Pacbitun ritually responded to macro-regional environmental stress. Ritual plant use at the cave sites does not conform to behavioral ecology models that predict biological, cost-fitness related responses to resource scarcity. Instead, the data supports a model of behavior based on culturally motivated ritual practices.
314

Creation of Chimera Through the Usage of an Inspirational System

Parish, Brandi Nicole 03 October 2013 (has links)
My thesis involves studying the nature of chimera through history and how certain aspects of chimeras represent specific features of dualities in human nature. The research was reflected in a series of sketches, where one sketch was finalized into a fully realized 3D model. To aid in this goal, I created a system that will randomly generate chimera based on different characteristics. This system was created using Max 5, and was programmed to place images with alphas on top of each other to create unique chimeras. The variables within this system are derived from the research on chimeras depicted in art and mythology throughout history, and will be used as an inspirational tool to help generate unique combinations of chimeras that may not otherwise have been imagined.
315

Indiana Jones and the Mysterious Maya: Mapping Performances and Representations Between the Tourist and the Maya in the Mayan Riviera

Batchelor, Brian 06 1900 (has links)
This thesis is a guidebook to the complex networks of representations in the Cob Mayan Jungle Adventure and Cob Mayan Village tours in Mexicos Mayan Riviera. Sold to tourists as opportunities to encounter an authentic Mayan culture and explore the ancient ruins at Cob, these excursions exemplify the crossroads at which touristic and Western scientific discourses construct a Mayan Other, and can therefore be scrutinized as staged post-colonial encounters mediated by scriptural and performative economies: the Museum of Maya Culture (Castaneda) and the scenario of discovery (Taylor). Tourist and Maya are not discrete identities but rather inter-related performances: the Maya become mysterious and jungle-connected while the tourist plays the modernized adventurer/discoverer. However, the tours foundations ultimately crumble due to uncanny and partial representations. As the roles and narratives that present the Maya as indigenous Other fracture, so too do those that construct the tourist as authoritative consumer of cultural differentiation.
316

Māyā, Puruṣa und Śiva die dualistische Tradition des Śivaismus nach Aghoraśivācāryas Tattvaprakāśavṛtti /

Gengnagel, Jörg. January 1900 (has links)
Thesis--Universität Tübingen, 1994. / Includes bibliographical references (p. [169]-176) and index. "Liste der in der Tattvaprakāśavṛtti zitierten Texte"-p. 180.
317

Hues, tresses, and dresses examining the relation of body image, hair, and clothes to female identity in Their eyes were watching God and I know why the caged bird sings /

Castaneda, Alisha Priolo. January 2010 (has links)
Thesis (M.A.)--Liberty University, 2010. / Includes bibliographical references.
318

Locating the place and meaning of the Talud-Tablero architectural style in the early classic Maya built environment

Cash, Cristin Loren. Guernsey, Julia E., January 2005 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Julia Guernsey. Vita. Includes bibliographical references.
319

Only a trickle? blood in detail and three women's films /

Field, Emma. January 2003 (has links)
Thesis (M.A.)--University of Tasmania, 2003. / Title from PDF t.p. (viewed on July 25, 2005). Electronic version of thesis lacks ill. found in printed version. Includes filmography (p. 116-119) and bibliographical references (p. 120-127).
320

Space, Settlement, and Environment: Detecting Undocumented Maya Archaeological Sites with Remotely Sensed Data

Vaughan, Andrew 11 August 2015 (has links)
This study utilizes an integrated remote sensing approach to augment settlement pattern research in the Yalahau Region of northern Quintana Roo, Mexico. The region has a long history of human occupation and an environment ranging from coasts, freshwater wetlands, forests, to fields and towns all above a porous karst geology. By utilizing various sensors (LiDAR, GeoEye and Landsat) and collection methods (satellite, aerial) as well as post-processing (band combinations, component analyses and indices) and cross-referencing the data, it is possible to generate a signature, which strongly correlates with evidence of prehistoric occupation. Field verification of a selection of identified signatures was conducted to assess the presence of human cultural material. The results of this investigation are presented together with other regional settlement pattern data in order to assess the status of a number of methodological and archaeological questions and supplement other regional data already available.

Page generated in 0.0515 seconds