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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.
381

Expressions of Maya identity and culture in Los Angeles : coloniality of power, resistance, and cultural memory

Batz, Giovanni 22 December 2010 (has links)
The migration of thousands of Guatemalan-Maya due to political violence and poverty since the 1970s led to the establishment of various diasporic communities throughout the United States. A frequent destination for the Maya is Los Angeles, California, where they are confronted with pressure to adapt within an environment that is predominately Latino/Hispanic. Maya identity expressed through the use of traje (Maya clothing), language, literature and spirituality is challenged by Euro-American culture such as western style of dress and the practice of English which discriminates against these customs. These conditions are more severe for Maya children who face the difficulties in preserving their heritage as a result of institutions such as public education which socializes them into US culture and history. Despite the presence of many indigenous communities in Los Angeles, such as the Maya, Mixtecos and Zapotecs, indigenous identity is almost non-existent in many public spaces and institutions. Discrimination against the Maya by their compatriots and other Latinos coupled with high rates of undocumented immigration statuses have contributed to this invisibility. Some Maya parents view the lack of a strong indigenous identity among their children as problematic and the source of negative cultural qualities such as disrespect towards elders, violence, individualism and misbehavior. In this study, I seek to examine Maya identity and culture in Los Angeles. What does it mean to identify as Maya in Los Angeles? What are the consequences of doing so? How do Maya immigrants respond to discrimination and what implications does discrimination have for the ethnic identity formation of their children? Why has Maya identity survived in some children of Maya and not in others? I found that while some Maya immigrants have assimilated into the Latino community in response to racism and fear of deportation, others have adopted strategies such as the use of marimba to preserve Maya identity which also serve to deal with a life of displacement and exile. Maya identity among children is highly influenced by factors such as the educational system, class and their parent’s willingness and ability to transmit Maya culture. Thus, while some children of Maya have been able to preserve and express their identity through various channels such as music and language, others may be unaware of, ashamed by or apathetic toward their indigenous roots and history. / text
382

Development of a suction detection system for a motorized pulsatile blood pump

Adnadjevic, Djordje 23 December 2010 (has links)
A computational model has been developed to study the effects of left ventricular assist devices (LVADs) on the cardiovascular system during a ventricular collapse. The model consists of a toroidal pulsatile blood pump and a closed loop circulatory system. Together, they predict the pump's motor current traces that reflect ventricular suck-down and provide insights into torque magnitudes that the pump experiences. In addition, the model investigates likeliness of a suction event and predicts reasonable outcomes for a few test cases. Ventricular collapse was modeled with the help of a mock circulatory loop consisting of a artificial left ventricle and centrifugal continuous flow pump. This study also investigates different suction detection schemes and proposes the most suitable suction detection algorithm for the TORVAD pump, toroidal left ventricular assist device. Model predictions were further compared against the data sampled during in vivo animal trials with the TORVAD system. The two sets of results are in good accordance. / text
383

Optimization of an array of peptidic indicator displacement assays for the discrimination of cabernet sauvignon wines

Chong, Sally 06 January 2011 (has links)
The research project, Optimization of an array of Peptidic Indicator Displacement Assays for the Discrimination of Cabernet Sauvignon Wines, describes the multiple step lab trials conducted to optimize an array of ensembles composed of synthesized peptides and PCV:Cu+2 complexes for the differentiation of seven Cabernet Sauvignon wines with different tannin levels. This report also includes the methods and analysis used. The analysis interpreted by principal component analysis. / text
384

Influence of ground motion scaling methods on the computed seismically-induced sliding displacements of slopes

Wang, Yubing 14 February 2011 (has links)
Evaluation of the seismic stability of slopes often involves an estimate of the expected sliding displacements. This evaluation requires a suite of acceleration-time histories as input motions. The methods of selecting and scaling these motions can affect the computed sliding displacements. Linear scaling of recorded ground motions and modification of recorded motions by spectral matching are common approaches used for ground motion selection and these approaches were used in this study to select motions for use in sliding displacement analyses. Rigid sliding block analyses and decoupled flexible sliding block analyses were performed using a suite of linearly scaled motions and a suite of spectrally matched motions. . Generally, the spectrally matched motions predict 10 to 30%, on average, smaller displacements and significantly less variability than the linearly scaled motions, when both suites of input motions were developed to match the same acceleration response spectrum. When both suites of input motions were developed to match the same peak ground velocity and acceleration response spectrum, the spectrally matched motions generally predict 5 to 15%, on average, larger displacements than the linearly scaled motions. Because ground motion parameters beyond acceleration response spectrum affect the computed sliding displacement, parameters such as peak ground acceleration (PGA), peak ground velocity (PGV) and mean period (T[subscript m]) should be considered in selecting and scaling motions for use in sliding displacement analyses. / text
385

Circuit breaker transient recovery voltage analysis with shunt capacitor bank configurations

Guha, Anirudh 21 February 2011 (has links)
Transient Recovery Voltage (TRV) is an important consideration in the selection and installation of circuit breakers with appropriate ratings. Capacitor banks with inrush current limiting reactors are an integral part of the power system. Capacitor banks with inrush reactors on the load side terminal of the capacitor breaker alter the TRV seen across the breaker and it is critical to carry out the TRV analysis to prevent circuit breaker failure. TRV analysis has been performed for various capacitor bank - inrush reactor configurations, with the fault occurring at different terminals on the load side. Analytical solutions have been presented for both single-phase and three-phase ungrounded capacitor banks. Neutral displacement voltage of three-phase ungrounded capacitor banks result in increased stress across the breaker. Results have been validated with PSCAD simulation and MATLAB plots. / text
386

Battle Hall : restoring natural ventilation in the Reading Room

Yen, Daniel Ka Kei 07 July 2011 (has links)
Battle Hall, located at the heart of the University of Texas at Austin’s campus since 1911, has been serving the University for a century. It was designed for cooling with natural ventilation prior to being fully air conditioned in the mid-1960s. The mechanical system currently installed in Battle Hall is over 40 years old. While it provides reasonable environment for the collections, it struggles to achieve stable conditions for various zones in the building. The purpose of this study is to consider isolating the Reading Room as an individual zone and explore the possibility of restoring natural ventilation as it was originally designed. There are various benefits in restoring natural ventilation to the hundred-year old Reading Room, including psychological benefits, indoor air quality, and energy savings. However, various concerns, such as environmental conditions, air pollutants, acoustic, and potential light damages, also exist. This study focuses on investigating the possibility of restoring natural ventilation by examining existing conditions, collection care requirements for library collections and historic architectural elements. Two data-loggers were placed in the Reading Room to record temperature and relative humidity readings for approximately five months. Through analysis of these readings of existing collection care settings and existing architectural settings, potential solutions and alternatives were considered and examined. These included non-action, hybrid natural ventilation, Johnson Controls Personal Environmental System, and HVAC shut-off. This study is the first of its kind for Battle Hall. As a Historic Structures Report of Battle Hall is commissioned by the University, this study provides a better understanding of potential solutions and alternatives to restore natural ventilation to Battle Hall. This may also serve as a platform to stimulate ideas and research on natural ventilation restoration to other buildings in the University. / text
387

Second Generation Navajo Relocatees: Inheriting Intergenerational Losses Due to P.L. 93-531

La Russo, Aresta January 2015 (has links)
This study examines the impacts of the United States federal policy Public Law 93-531, the Navajo Hopi Land Settlement Act, which was passed by Congress in 1974. P.L. 93-531 forced many Navajo families and their children who had resided on their traditional homeland for generations to relocate elsewhere. Today, Navajo residents who were minors when they relocated with their parent(s) find themselves dispossessed of their cultural heritage. Basically, P.L. 93-531 dispossessed and displaced the Navajo minors (now adults) from their inherent traditional homelands, thus creating a second generation of Navajo relocatees. The relocation plan was not inclusive of second generation Navajo relocatees as stakeholders, leaving them in an indeterminate legal, economic, political, and social state. The primary questions addressed are these, 1) How has the relocation experience, due to Public Law 93-53, impacted the lives of second generation Navajo children, now adults, living in towns or cities off the Navajo Nation? What have been the perspectives and challenges of the participants after relocation? 2) What has the federal and Navajo government’s role been in the lives of Children of Relocation? The study utilizes a modified theoretical framework, Peoplehood Matrix, which encompasses the components of, language, ceremonial cycle, land, and sacred history, with the addition of livelihood. The components of the modified Peoplehood Matrix are interwoven and dependent upon one another which contribute to a group or individuals identity (Holm, Pearson and Chavis 2003). Qualitative and quantitative methodologies of collecting artifacts, a Q-method survey, and in-depth interview are used to study the second generation Navajo relocatees as adults living away from the Navajo Nation to document the challenges they experienced as a result of compulsory relocation. Although few studies address Navajo adult relocatees, there are no significant studies addressing second generation Navajos relocatees.
388

Διερεύνηση ανθεκτικότητας κατασκευών οπλισμένου σκυροδέματος μέσω μη γραμμικών αναλύσεων μεγάλων παραμορφώσεων

Ρόμπολας, Ιωάννης 12 June 2015 (has links)
Το ζήτημα της σταδιακής κατάρρευσης ήρθε στο προσκήνιο με την κατάρρευση του κτηρίου Ronan Point Apartment Building στο Ηνωμένο Βασίλειο, το 1968. Με αφορμή το γεγονός αυτό, σχεδόν το σύνολο των κανονισμών οπλισμένου σκυροδέματος ανά τον κόσμο απέκτησε διατάξεις σχετικά με την προστασία κατασκευών από σταδιακή κατάρρευση. Στα πλαίσια αυτού, εξετάζονται δύο διατάξεις πλακολωρίδας δύο ανοιγμάτων υπό το σενάριο της κατάρρευσης της ακραίας στήριξης. Η πρώτη διάταξη είναι οπλισμένη κατά τα συνήθη πρότυπα, ενώ η δεύτερη περιλαμβάνει επιπλέον οπλισμό στο άνω πέλμα των ανοιγμάτων. Οι αναλύσεις διεξάγονται σε περιβάλλον πεπερασμένων στοιχείων ANSYS και συγκρίνονται με αντίστοιχα πειραματικά αποτελέσματα. Συμπεραίνεται ότι οι συνήθεις πλάκες δεν έχουν την δυνατότητα ανάπτυξης μεγάλων μετατοπίσεων και ότι η προσθήκη οπλισμού στο άνω πέλμα των ανοιγμάτων των πλακών προσδίδει σε αυτές την απαραίτητη πλαστιμότητα, ώστε να μπορούν να αναπτύξουν μεγάλεις μετακινήσεις και να αναπτύσσονται δυνάμεις ελκυστήρα. / The issue of progressive collapse came to the foreground with the collapse of the Ronan Point Building in the UK, in 1968. In response to this event, most reinforced concrete codes around the work integrated regulations in regard to protection of buildings against progressive collapse. Two two-span slab assemblies are analysed for the collapse of the outer support. The first assembly is reinforce according to the common practice, while the second has added reinforced to the top end of the spans. The analyses are performed with ANSYS and compared with experimental results. It is concluded that commonly reinforced slabs do not have the ability to withstand large deflections. Additional top end reinforcement gives slabs the necessary plasticity in order for large deflections to be developed and tension (tie) forces to build up in the section.
389

Εκτόπιση νευτωνικών και μη νευτωνικών ρευστών από αγωγούς μεταβαλλόμενης διατομής

Δημακόπουλος, Ιωάννης Ε. 10 March 2009 (has links)
- / -
390

Data Assimilation In Systems With Strong Signal Features

Rosenthal, William Steven January 2014 (has links)
Filtering problems in high dimensional geophysical applications often require spatially continuous models to interpolate spatially and temporally sparse data. Many applications in numerical weather and ocean state prediction are concerned with tracking and assessing the uncertainty in the position of large scale vorticity features, such as storm fronts, jets streams, and hurricanes. Quantifying the amplitude variance in these features is complicated by the fact that both height and lateral perturbations in the feature geometry are represented in the same covariance estimate. However, when there are sufficient observations to detect feature information like spatial gradients, the positions of these features can be used to further constrain the filter, as long as the statistical model (cost function) has provisions for both height perturbations and lateral displacements. Several authors since the 1990s have proposed various formalisms for the simultaneous modeling of position and amplitude errors, and the typical approaches to computing the generalized solutions in these applications are variational or direct optimization. The ensemble Kalman filter is often employed in large scale nonlinear filtering problems, but its predication on Gaussian statistics causes its estimators suffer from analysis deflation or collapse, as well as the usual curse of dimensionality in high dimensional Monte Carlo simulations. Moreover, there is no theoretical guarantee of the performance of the ensemble Kalman filter with nonlinear models. Particle filters which employ importance sampling to focus attention on the important regions of the likelihood have shown promise in recent studies on the control of particle size. Consider an ensemble forecast of a system with prominent feature information. The correction of displacements in these features, by pushing them into better agreement with observations, is an application of importance sampling, and Monte Carlo methods, including particle filters, and possibly the ensemble Kalman filter as well, are well suited to applications of feature displacement correction. In the present work, we show that the ensemble Kalman filter performs well in problems where large features are displaced both in amplitude and position, as long as it is used on a statistical model which includes both function height and local position displacement in the model state. In a toy model, we characterize the performance-degrading effect that untracked displacements have on filters when large features are present. We then employ tools from classical physics and fluid dynamics to statistically model displacements by area-preserving coordinate transformations. These maps preserve the area of contours in the displaced function, and using strain measures from continuum mechanics, we regularize the statistics on these maps to ensure they model smooth, feature-preserving displacements. The position correction techniques are incorporated into the statistical model, and this modified ensemble Kalman filter is tested on a system of vortices driven by a stochastically forced barotropic vorticity equation. We find that when the position correction term is included in the statistical model, the modified filter provides estimates which exhibit substantial reduction in analysis error variance, using a much smaller ensemble than what is required when the position correction term is removed from the model.

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