Effective models of vibratory screens which can capture the true response characteristics are crucial in the understanding of faults and failures which occur in vibratory screens. However, the current available models are usually simplified and have limited validation to that of a physical screen. Much research has been conducted to optimise the screening efficiency of screens. The optimisation includes screen geometry, material processing of the screen and the dynamic response of the screen. These investigations have not been furthered to investigate the effects of different faults on the dynamic response of a vibratory screen. To model a vibratory screen which can replicate the dynamics of a physical vibratory screen it is important to create a model with enough complexity to capture the dynamics of the screen. The model of the screen was validated using both modal analysis and the transient response of the screen. The modal analysis was used to ensure that the physical characteristics of the model are consistent with that of the physical screen. Once this was completed, the second validation aimed to investigate if the model of the screen could capture transient faults which are measured experimentally. It was found that it was not possible to conclusively determine if the finite element methods model could Finally, an intelligent method was used to distinguishing between different faults and classifying them accordingly. The intelligent method was also trained using the FEM data and then used to classify the physical screen data. / Dissertation (MEng)--University of Pretoria, 2020. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

With the continued expansion in access to touchscreen devices, the question of whether such interactions are beneficial to the preschool user is increasingly important. Touchscreens allow for contingent responses from the viewer, a feature that is now utilized by the new modality of interactive television. This dissertation study investigates whether the addition of full interactivity to an educational cartoon facilitates narrative comprehension and learning of STEM-based curriculum. Forty-seven 4- to 5- year-olds watched a researcher-developed cartoon about two characters who were learning about the concept of rotation in outer space. Same-gender and age matched pairs individually watched the cartoon and were assessed on measures of narrative comprehension and, after a two-week delay, on a measure of rotation knowledge learning. Participants in the active condition watched the cartoon with the ability to make 5 character decisions at different points throughout the video. Those children in the passive condition saw the same path determined by their active pair, without any choice points. Results indicated that learning, as demonstrated on transfer items, was enhanced by the addition of choice, albeit no immediate gains in story understanding. The implications for interactive cartoons targeted to the age range in the context of differential access to family resources are discussed.

The rising interest in fan performance in the presence of total pressure distortion, a topic of fundamental interest for integrated airframe/engine architectures, has led to increased research in ground based testing environments. Included in these studies is the generation of simulated total pressure distortion profiles using wire mesh screens. Although the inlet duct development of total pressure distortion patterns has been studied in a historical context when distortion effects on engine performance were first of interest, these were typically simplified experimental studies for low-speed flows. To aid in the understanding of total pressure distortion development approaching a transonic fan face, a series of experiments were conducted to detail the development of such a profile downstream of the screen plane in the absence and presence of fan effects. Presented is an extensive experimental set to detail (1) the evolution of a screen-generated total pressure distortion profile as it develops in a constant diameter inlet duct and (2) the effect that a single stage transonic fan has on the distortion development. Included is a detailed analysis of the distortion profile characteristics for increasing development length, and the behavioral changes of the profile when fan blockage is present near the screen plane. Recommendations are made regarding the placement of total pressure distortion screens relative to the fan face, and insights are given into the expected profile evolution. This work is a contributing part of an ongoing systematic investigation of fan performance when subjected to screen-generated total pressure inlet distortion. / Master of Science

No description available.

No description available.

Yes / This chapter deals with a range of issues related to the structure and appearance of Augmented Public Space in terms of framing. It also develops key theoretical perspectives concerning the ways that information and media content is superimposed onto the urban environment. In doing so, it analyses the importance of locality on the character of display and argues that in the long run it is the body that is central to the framing of content and so is crucial to our understanding of augmented public space. This is exemplified in the widespread adoption of urban screens in UK city centres which forms a case study, but is not exclusive in its application to urban screens. The issues dealt with are relevant to all forms of augmented public space and in any situation where the built environment coexists with layers of information and media content ¿ the ¿media layer¿.

A house in the mid-west located on the prairie. A "get-away" from the busy city of Chicago, a place of quiet repose. View of the horizontal is intensified by various planes of crops and the plinth. Fields of crops descend in height to allow the house to rise up and breathe. A simple grid provides inspiration and gives structure. A house full of screens provides changing spaces and adjustable levels of privacy and protection. Views of one screen layered with another provide changing patterns. / Master of Architecture

No description available.

Section 316(b) of the Clean Water Act requires thermal power generating facilities to minimize adverse environmental impact resulting from the operation of cooling water intake structures (CWIS). Adverse environmental impact can occur when aquatic organisms are impinged on traveling water screens. Modified traveling screens were developed to improve the post-impingement survival of organisms. These screens have been used at a few power plants and are now being considered at additional facilities to reduce the mortality of juvenile and adult fish. Existing biological efficacy data show that post-impingement survival is highly variable by species. The majority of previous installations are at estuarine facilities. As such, there is a lack of biological efficacy data with many of the freshwater species commonly impinged at CWIS. In addition, most of the existing modified screen installations were installed prior to 1990. Since that time, improvements in screen designs have increased survival. For these reasons, the existing biological efficacy of the new screen designs was limited and largely unknown for many freshwater species. The mortality, injury, and scale loss rates of 10 species of freshwater fish impinged and recovered with a modified traveling screen were evaluated in the laboratory. Species tested included: golden shiner (Notemigonus crysoleucas); fathead minnow (Pimephales promelas); white sucker (Catostomus commersoni); bigmouth buffalo (Ictiobus cyprinellus); channel catfish (Ictalurus punctatus); hybrid striped bass (Morone chrysops × M. saxatilis); bluegill (Lepomis macrochirus); largemouth bass (Micropterus salmoides); yellow perch (Perca flavescens); and freshwater drum (Aplodinotus grunniens). Fish were impinged at 0.3, 0.6, or 0.9 m•s-1 velocity. Mortality, injury, and scale loss rates were generally low. Mortality rates did not exceed 5% for any species and velocity tested, indicating that this technology has potential to substantially reduce impingement mortality at CWIS. Despite a general trend toward increasing mortality at higher velocities, velocity was only a significant factor in the mortality of bluegill (P=0.0005). Injury and scale loss rates were low for most species tested, although they were more variable than observed rates of mortality. There was a trend toward lower mortality, injury, and scale loss in larger fish. In all cases where fish length was a significant factor (P<0.05), the pattern of decreasing mortality, injury, and scale loss as fish increased in length was constantly observed. Additional tests were undertaken with channel catfish, fathead minnow, and golden shiner to assess the effect of duration of impingement on mortality, injury, and scale loss. Longer durations of impingement appeared to result in higher mortality, injury, and scale loss, especially at durations of impingement greater than 6 minutes. However, longer durations of impingement could be avoided at most cooling water intake structures by continuously rotating screens.

Regulatorische Landschaften von Genen steuern das präzise transkriptionelle Programm, das für die embryonale Entwicklung notwendig ist. Transkriptionsfaktoren (TFs) interagieren dabei mit regulatorischen Elementen (REs), um die Genexpression zu kontrollieren. Zur Untersuchung der zugrundeliegenden Mechanismen konzentriere ich mich auf das Xist-Gen, den Hauptregulator der X-Chromosom-Inaktivierung (XCI) in Säugetieren. In der Embryonalentwicklung wird Xist monoallelisch in weiblichen Zellen aktiviert, woraufhin die Xist-RNA das X-Chromosom überzieht und dessen Inaktivierung einleitet. Dadurch wird die erhöhte Dosis X-chromosomaler Gene in weiblichen Zellen kompensiert. Um ein umfassendes Verständnis der Xist-Regulatoren zu erhalten, nutze ich CRISPR-Screens, um REs und TFs in weiblichen embryonalen Stammzellen zu untersuchen. Dabei identifiziere ich ein neues nicht-kodierendes Gen namens Xert. Daruberhinaus stelle ich fest, dass promotor-nahe REs auf die Anzahl der X-Chromosomen reagieren, während distale REs unbeeinflusst bleiben. Durch meine TF-Screens entdecke ich zwei Gruppen von Aktivatoren: Die frühe Gruppe, darunter der X-chromosomale Faktor ZIC3, zeigt in weiblichen Zellen erhöhte Expression, was darauf hindeutet, dass sie die Xist-Expression auf weibliche Zellen beschränken. Die späte Gruppe, einschließlich OTX2, agiert geschlechtsunabhängig und stellt nach der initialen Xist-Aktivierung ein hohes Transkriptionslevel sicher. Mit weiteren CRISPR-Screens verknüpfe ich TFs mit REs und zeige, dass frühe Aktivatoren promotor-nahe REs beeinflussen, während späte Aktivatoren distale REs stärker regulieren. Diese Arbeit liefert eine systemische Perspektive des trans- und cis-regulatorischen Netzwerks, das die Xist-Aktivierung während der Differenzierung koordiniert und die Beschränkung auf weibliche Zellen gewährleistet. / The regulatory landscapes of developmental genes orchestrate precise and coordinated transcriptional programs required for embryonic development. During this process, transcription factors (TFs) interact with regulatory elements (RE) to finely tune gene expression. To study the regulatory principles acting in this context, I focus on the Xist gene, the master regulator of X-chromosome inactivation (XCI) in mammals. During early development, Xist is upregulated in a monoallelic fashion specifically in females. The Xist RNA then coats the X chromosome in cis, resulting in its inactivation. In this manner, female cells compensate for their increased X-chromosomal dosage in comparison to males. To obtain a complete understanding of Xist regulation, I first perform two CRISPR screens targeting REs and TFs during the early differentiation of female mouse embryonic stem cells. I identify Xist-controlling REs within the locus, unveiling a novel non-coding gene Xert. I further demonstrate the sensitivity of promoter-proximal REs to X-dosage, contrasted by the behavior of distal REs. In the TF screen, I detect two sets of activators which undergo transient upregulation at the onset of XCI. The early group of activators, including the X-linked TF ZIC3, exhibits higher expression levels in XX cells, indicating a role in restricting Xist expression to females. The late group of activators, including the master regulator of the epiblast OTX2, drives high transcript levels following Xist activation. Subsequently, I use a series of CRISPR screens targeting individual reporter constructs to map TF-RE wiring at the locus. I find that the early activators primarily act on the XX-dependent proximal REs. Contrary, the late activators interact with the sex-independent distal REs. With this study, I provide a systems level perspective of the trans- and cis-regulatory network that links Xist activation to early differentiation and ensures female-specificity.