Zincor, a refinery in South Africa, uses the conventional roast-leachelectrowinning process to produce zinc metal. The roasting process of ZnS concentrate makes use of four Lurgi fluidized bed roasters to produce calcine (contains ZnO and ZnFe2O4 as zinc products) and SO2 gas. The roasting plant consists of two 18 m2 and two 35 m2 cross sectional area roasters. Prior to 1996, Zincor utilized air as the only oxidant and fluidizing medium in its roasters. The maximum dry feed rates that the roasters could process were 6.5 t/d.m2. In an attempt to increase production, oxygen enrichment was first trialled and then introduced into the fluidizing air. The ability of oxygen enrichment to increase the rate of the ZnS oxidation reaction allowed higher feed rates to the roasters. This was successful and oxygen enrichment was permanently implemented. That enabled dry feed rates to be maintained at 7.0 t/d.m2 and 7.3 t/d.m2 for the small and big roasters respectively. Oxygen enrichment up to 26% in the fluidizing air is utilized. Due to the highly competitive nature of the zinc industry, innovative processing techniques are necessary to be competitive. The aim of this study is to determine whether oxygen enriched air can be reduced by introducing micro-pelletized concentrate into the roaster feed blend, whilst maintaining current roaster feed rates and calcine quality. This study was executed in four parts. Firstly, the role entrainment played in influencing average particle residence time. Secondly, a study of production methods for stable micro-pellets. Thirdly, a study of the influence of oxygen enrichment and particle size on the roasting of micropellets. The fourth part of the study was introduction of micro-pellets into the Zincor roasters to determine whether oxygen enrichment could be reduced. The particle size distribution of a blend of feed concentrate to the roasters is 50% passing approximately 48 μm. This leads to entrainment values between 87% and 91%. The micro-pelletization process reduces the –500 μm fraction from 87% to 10%, which degrades to 30% during roasting. This requires that approximately 48% of the concentrate needs to be micro-pelletized to restore the 70% designed entrainment target. It was determined that entrained particles spend on average 0.46 hr to 2.44 hr in the bed compared to particles in the overflow that have residence times between 3.93 and 4.00 hr. The calculated times for entrainable particles are somewhat higher and for the bed overflow lower compared to the values measured by Spira, 1970. The required reaction time for micropellets was found to be far below their residence time inside a Zincor roaster. With a load of 20% micro-pellets introduced into the feed concentrate, the oxygen enrichment could be reduced by 60%. The quality of the calcine produced was maintained above the target of 98.8% ZnS to ZnO conversion. The results of this study have shown that the use of micro-pelletization of concentrate at Zincor reduces entrainment of particles successfully. Manipulation of entrainment through micro-pelletization can be used successfully to reduce oxygen enrichment, whilst improving production and maintaining quality at Zincor. Copyright / Dissertation (MEng)--University of Pretoria, 2009. / Materials Science and Metallurgical Engineering / unrestricted

By studying how captive animals use outdoor space, we can determine which areas fulfill their biological and behavioral needs to improve enclosure design for animal welfare and visitor experience. The aim of the study was to determine the differential use of outdoor space in a mixed exhibit of captive ring-tailed lemurs (Lemur catta) and red ruffed lemurs (Varecia rubra), and to assess both the effect of adding environmental enrichment and possible visitor and meteorological effects on the lemurs’ use of space and behavior. For one month, five-minute interval scan sampling was used to record lemur location and behavior, as well as the meteorological conditions and presence of zoo visitors in the lemurs’ outdoor enclosure. That baseline was followed by four alternating two-week periods of food or structural enrichment, both with and without visitors. Enrichment increased the lemurs’ use of the enriched sectors, decreased resting, and increased locomotion. Structural enrichment increased their exploratory behaviors and stimulated arboreal locomotion. Both species preferred sunny and warm conditions for sunbathing and resting, while moving more around the enclosure in cooler and cloudier weather. The visitor effect on the lemurs’ use of space was weaker than the effects of enrichment and meteorological conditions. The availability of areas to hide and possible habituation to humans may have played a role in the reduced visitor effect. The results of the study showed inter-specific differences in the lemurs’ use of space and behavior and a complex combined effect of enrichment, visitor presence and meteorological conditions.

The Chesapeake Bay, once one of the worlds most productive estuaries, has been severely impacted by human activity in the water and on the lands around it. Viewed as an ecosystem, the Bay is no longer able to support the variety and abundance of biota that it was historically able to. Several decades of research on the Chesapeake have pointed to human activities as being the principle reason for this decline. Of these detrimental activities, elevated inputs of Nitrogen and Phosphorus to the Bay were singled out as being the greatest cause of water quality deterioration. The state of Virginia is trying to reduce its annual load of Nitrogen, to the Potomac River, to 60% of what the load was estimated to be in 1985. Virginia would like to accomplish this goal at the lowest cost to its citizens. Therefore the state needs to determine the combination of nitrogen control efforts which will achieve the goal at the lowest cost. The state would also like to be able to maintain nitrogen loads at or below this cap level, indefinitely into the future. This study was undertaken with three primary objectives. The first was to project the level of annual nitrogen inputs to the Potomac River, from the state of Virginia, over the next 15 years. The second was to estimate the minimum annual costs necessary to achieve and maintain a 40% reduction in total nitrogen inputs, using the Virginia's estimated 1985 inputs as a baseline. The final objective was to assess the potential cost savings that may result from using one of two alternative development patterns within the rapidly urbanizing Northern Virginia portion of the Potomac Watershed. The first alternative is prohibiting low-density development within the Northern Virginia region, and the second is to restrict all new development to be within 5 miles of an existing urban area. Study results suggest that there has been no significant progress toward meeting the nitrogen reduction goal, due to the increase in population within the watershed, over the past 13 years. To attain the goal in 1998, a minimum of $27 million, above what is currently being spent annually, would be required. Under the current land use trend within Virginia's Potomac Basin, the annual cost for maintaining the goal is estimated to rise to $38 million annually, in 1998 dollars, by the year 2013. This is a 40% increase in cost. If the first alternative development pattern is adhered to over this 15-year period, then the annual cost will be $33 million, for an annual cost saving of approximately $5 million in 2013. The second alternative could achieve similar results if implemented, costing roughly $5 million less in 2013 than the annual cost per year under the current trend. These findings suggest that the use of alternative development patterns can help slow but not prevent the annual cost, of maintaining the cap, from rising. The study indicates that the reason for the continuous rise in annual cost, over this fifteen-year period, is due primarily to an increase in nitrogen loading to the Potomac that will result from the wastewater disposal needs of the growing population within the Basin. Furthermore, the state will eventually exhaust its lower cost options for reducing Nitrogen loadings, and at that point the annual cost for maintaining the Nitrogen Cap will begin to rise exponentially. Under current land use trends this rapid rise in cost is unlikely to occur within the next 15 years, and is more apt to occur sometime within the next 20 to 40 years. Once annual expenditures begin to rise exponentially it is unlikely that the state of Virginia would be able to maintain its 40% reduction goal. / Master of Science

Thesis (M. Com. (Human Resource Management)) -- University of Limpopo, 2021 / The purpose of this study was to examine the relationships among organisational politics, organisational support and job satisfaction among 148 participants in a selected institution of higher education in South Africa. Quantitative, descriptive research was conducted to determine if there is a relationship among the three variables of the study. Data collection was done using structured questionnaires. Two groups of respondents participated in the study; and that is the academic staff and administrative staff members from central administration and library. The study established that organisational politics is negatively related to organisational support and have a negative impact on the overall job satisfaction. Based on the findings of the study, recommendations, strengths and potential links for future research are provided. Key words/concepts: Organisational Politics, Organisational Support, Job Satisfaction.

In the light of major changes affecting the workplace, the present research investigates the interaction of life domains. Specifically, the studies included in this research comprehensively integrate conceptual advancements in the literature on the interaction of life domains. These advancements refer to the scope of the life domains considered, the different directions of interactions between the work and the private life domain, the inclusion of a positive perspective on the interplay, and the adoption of multi-time and multi-level research methodology. At the same time, the present research adopts new perspectives by investigating life domain conflict and enrichment from an international perspective, by integrating boundary management tactics and by considering the role of emotions at the workplace. Four different studies based on different international and domestic samples were conducted. The results of the first study demonstrate that life domain enrichment plays an important role for international assignees and contributes to the prediction of important outcomes beyond what is contributed by life domain conflict. Using a large international sample, the second study underlines the need to take cultural value dimensions into account when examining the interplay of life domains. This study indicates that Individualism/Collectivism moderate the relationship between life domain conflict and satisfaction outcomes, such that the relationship is stronger in cultures high on Individualism. In the third study, the impact of boundary management tactics for the interplay of different life domains is shown for a sample of expatriates. Specifically, the third study demonstrates that permeability and flexibility of life domains are associated with life domain conflict and enrichment. Finally, the fourth study adopts a longitudinal research design using a weekly diary approach. This study indicates that daily affective events and mood predict life domain conflict and enrichment over time. Taken together, the present studies demonstrate that the integration of conceptual advancements with recent trends at the workplace substantially contribute to our knowledge on life domain interactions and open promising avenues for future research. At the same time, this integration provides several implications for organizations and individuals for the successful management of the interplay of life domains in a modern workplace.

Cette recherche s’intéresse au vécu des célibataires géographiques dans la marine nationale. Le but de ce travail est, d’une part, de comprendre leur ressenti de l’interface travail-famille et de la satisfaction professionnelle et, d’autre part, d’analyse le lien entre ces deux variables et la relation qu’elles entretiennent avec le turnover volontaire. Nous faisions l’hypothèse que les célibataires géographiques ressentiraient davantage de conflit travail-famille et d’insatisfaction professionnelle que les marins qui n’étaient pas dans cette situation. De plus, la satisfaction professionnelle a été envisagée comme un antécédent du vécu de l’interface travail-famille. Finalement, nous faisions l’hypothèse que le lien entre satisfaction et interface travail-famille aurait une répercussion sur le turnover volontaire. Pour tester ces différentes hypothèses, une étude qualitative et trois études quantitatives ont été réalisées sur 5 787 marins. Il existe bien des différences entre célibataires géographiques et non célibataires géographiques. De plus, la satisfaction professionnelle réduit l’apparition du conflit et augmente l’enrichissement. Indépendamment de la situation maritale, l’insatisfaction professionnelle et le conflit travail-famille augmentent le risque de turnover volontaire chez les marins. Le lien entre insatisfaction et départ volontaire est médié par le conflit travail-famille. / This research studies the experience of geographical celibacy in French Navy. The aim of this study is, on the one hand, to understand their perception of work-family conflict and enrichment and job satisfaction, and, on the other hand, to analyze the link between these two variables and the relationship they have with voluntary turnover. We hypothesized that geographical celibates feel more work-family conflict et job dissatisfaction than sailors that weren’t in that situation. Moreover, job satisfaction was considered as an antecedent of the experience of work-family interface. Finally, we hypothesized that the link between satisfaction and work-family interface would cause voluntary turnover. To test these different hypotheses, one qualitative and three quantitative studies were realized on 5 787 sailors. There are differences between geographical celibates and non-geographical celibates. In addition, job satisfaction reduces the appearance of conflict and increases enrichment. Independently of marital situation, job dissatisfaction and work-family conflict raise the risk of voluntary turnover of the sailor. The link between job dissatisfaction and voluntary turnover is mediated by work-family conflict.

Cette thèse aborde les problématiques liées à la construction de Topic Maps et à leur utilisation pour la recherche d’information dans le cadre défini par le Web sémantique (WS). Le WS a pour objectif de structurer les informations disponibles sur le Web. Pour cela, les ressources doivent être sémantiquement étiquetées par des métadonnées afin de permettre d'optimiser l'accès à ces ressources. Ces métadonnées sont actuellement spécifiées à l'aide des deux standards qui utilisent le langage XML : RDF et les Topic Maps. Un contenu à organiser étant très souvent volumineux et sujet à enrichissement perpétuel, il est pratiquement impossible d’envisager une création et gestion d’une Topic Map, le décrivant, de façon manuelle. Plusieurs travaux de recherche ont concerné la construction de Topic Maps à partir de documents textuels [Ellouze et al. 2008a]. Cependant, aucune d’elles ne permet de traiter un contenu multilingue. De plus, bien que les Topic Maps soient, par définition, orientées utilisation (recherche d’information), peu d’entre elles prennent en compte les requêtes des utilisateurs.Dans le cadre de cette thèse, nous avons donc conçu une approche que nous avons nommée ACTOM pour « Approche de Construction d’une TOpic Map Multilingue ». Cette dernière sert à organiser un contenu multilingue composé de documents textuels. Elle a pour avantage de faciliter la recherche d’information dans ce contenu. Notre approche est incrémentale et évolutive, elle est basée sur un processus automatisé, qui prend en compte des documents multilingues et l’évolution de la Topic Map selon le changement du contenu en entrée et l’usage de la Topic Map. Elle prend comme entrée un référentiel de documents que nous construisons suite à la segmentation thématique et à l’indexation sémantique de ces documents et un thésaurus du domaine pour l’ajout de liens ontologiques. Pour enrichir la Topic Map, nous nous basons sur deux ontologies générales et nous explorons toutes les questions potentielles relatives aux documents sources. Dans ACTOM, en plus des liens d’occurrences reliant un Topic à ses ressources, nous catégorisons les liens en deux catégories: (a) les liens ontologiques et (b) les liens d’usage. Nous proposons également d’étendre le modèle des Topic Maps défini par l’ISO en rajoutant aux caractéristiques d’un Topic des méta-propriétés servant à mesurer la pertinence des Topics plus précisément pour l’évaluation de la qualité et l’élagage dynamique de la Topic Map. / The research work in this thesis is related to Topic Map construction and their use in semantic annotation of web resources in order to help users find relevant information in these resources. The amount of information sources available today is very huge and continuously increasing, for that, it is impossible to create and maintain manually a Topic Map to represent and organize all these information. Many Topic Maps building approaches can be found in the literature [Ellouze et al. 2008a]. However, none of these approaches takes as input multilingual document content. In addition, although Topic Maps are basically dedicated to users navigation and information search, no one approach takes into consideration users requests in the Topic Map building process. In this context, we have proposed ACTOM, a Topic Map building approach based on an automated process taking into account multilingual documents and Topic Map evolution according to content and usage changes. To enrich the Topic Map, we are based on a domain thesaurus and we propose also to explore all potential questions related to source documents in order to represent usage in the Topic Map. In our approach, we extend the Topic Map model that already exists by defining the usage links and a list of meta-properties associated to each Topic, these meta-properties are used in the Topic Map pruning process. In our approach ACTOM, we propose also to precise and enrich semantics of Topic Map links so, except occurrences links between Topics and resources, we classify Topic Map links in two different classes, those that we have called “ontological links” and those that we have named “usage links”.

African savanna elephants (Loxodonta africana) and Asian elephants (Elephas maximus) are a focus of welfare research in zoos due to their high intelligence, complex social structure, and sheer size. Due to these challenges, some argue that zoos are inherently incapable of providing appropriate care for elephants, while others believe that zoos can fulfill the needs of these species with improved husbandry. There is a general consensus from both within and outside of zoos, however, that zoos must improve their elephant programs or cease exhibiting these animals altogether. Now more than ever, applied research on zoo elephant welfare is needed to provide context for this debate. Researchers are interested in how far zoo elephants walk due to the potential health and welfare benefits of walking in these highly mobile species. Zoo researchers recently adopted GPS technology to study elephant walking, and preliminary evidence suggests that African elephants in large zoo exhibits walk distances that correspond with wild elephants under non-extreme conditions. However, data are limited from Asian elephants and from elephants in more typically-sized exhibits. In Chapter Two, I discuss important methodological considerations of utilizing GPS in a zoo environment, including an introduction to the technology, sources of error and mitigation, methods to improve GPS performance, and possible effects of GPS device attachment on animal behavior. This review shows GPS performance is adequate for tracking zoo elephant walking when proper methodological techniques are applied, and should serve as a useful reference for zoo researchers considering using GPS. In Chapter Three, I used GPS anklets to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 zoos. I collected 259 days of data and found that elephants walked an average of 5.34 km/day with no significant difference between species. Multivariate regression models predicted that elephants with more dynamic feeding regimens (more diverse feeding types and frequencies; unscheduled feeding times) will walk more. Distance walked was also predicted to be higher in elephants that spend time in a greater number of different social groups. Distance walked was predicted to decline with age. Finally, I found a significant negative correlation between distance walked and nighttime space experience. The results of the analysis suggest that zoos that want to increase walking in their elephants need not rely solely on larger exhibits, but can increase walking by adding quality and complexity to exhibits. However, my results failed to establish a definitive link between walking distance and other validated measures of elephant welfare. Thus, the direct health and welfare benefits of walking in zoo elephants remain unresolved. Resting behaviors are an essential component of animal welfare, but have received little attention in zoological research. In Chapter Four, I used accelerometers in anklets to complete the first large-scale multi-species investigation of zoo elephant recumbence. I collected 344 days of data from 72 adult female African (n = 44) and Asian (n = 28) elephants at 40 zoos. I found that African elephants are recumbent an average of 2.14 hours/day, which is significantly less than Asian elephants at 3.22 hours/day. Multivariate regression models predicted that African elephant recumbence increases when they experience more space at night, and Asian elephant recumbence increases when they spend time housed alone. Both species showed a similar response to substrate, such that African elephants spending time on all-hard substrates are predicted to be recumbent less, while Asian elephants spending time on all-soft substrates are predicted to be recumbent more. The discovery that occasional non-recumbence is a common behavior in zoo elephants also introduces a new area of research that may have important animal welfare consequences. Finally, this study established that zoos should continue their efforts to replace hard substrate with soft substrate in order to provide zoo elephants with environments that facilitate recumbence. Overall, this work assessed walking and recumbence in zoo elephants, which will allow zoos to gauge the prevalence of these behaviors in their elephants as compared to the sub-population studied here. A variety of factors that are associated with these behaviors were also identified. With this information, zoos can prioritize modifications to their facilities and animal management programs to create an environment that encourages zoo elephants to express walking and recumbence behavior, should they choose to do so. This work is one component of the Elephant Welfare Project, the largest zoo animal welfare project ever undertaken, and is unprecedented in both scope and scale. The project was funded by the Institute of Museum and Library Services (IMLS), an independent, U.S., federal, grant-making agency that supports libraries, museums, and zoos. At the time of this writing, the first manuscripts from this project are being submitted to academic journals. These papers will describe the prevalence and distribution of a variety of elephant behaviors and welfare indicators, serve as a benchmark for future elephant welfare studies, and aid in decision making with regard to best practices in elephant management.

<p>Recent developments in Artificial Intelligence (AI) and Machine Learning (ML) have not only revolutionized engineering but also the way humanity foresees the future with machines. From self-driving cars to large language models and ChatGPT, AI and ML will continue to redefine the boundaries of innovations and reshape the way we interact with the world. The anticipated benefits are transformative, enabling enhanced productivity, improved decision-making, and the potential for significant cost savings. These developments in AI/ML and the promise for improved reliability, anomaly detection, efficient operation, etc., have unavoidably caught the attention of nuclear engineers. Advancing nuclear predictive models and providing real-time support with regard to operation and maintenance are just a few of the potential tasks AI/ML could provide assistance. Microreactors is just one example of future nuclear systems where semi-autonomous operation and fully digital instrumentation and control with AI/ML-based decision support would be required for cost-effective deployment in remote areas.</p><p>However, the world of nuclear engineering is skeptical of the direct application of AI/ML at nuclear facilities mostly due to limited past experience, potential high risk for false negatives, and limited amount of available data to demonstrate widespread applicability with high confidence. In order to curb these worries and take advantage of recent public interest in AI/ML, publicly available, real-time datasets need to be created. In this thesis, a universal AI/ML dataset is developed takes advantage of the recent digitization of Purdue University Reactor One (PUR-1) and using real-time data directly from PUR-1. The expectation is to follow the paradigm of the AI/ML community where open datasets (e.g., Kaggle, ImageNet, etc.) were the stepping stone towards new algorithms, facilitating collaborative problem-solving, and driving breakthroughs in the field of AI/ML through open competitions and knowledge sharing.</p><p>PUR-1 is capable of providing real-time research data to the second for over 2000 different parameters ranging from physical components such as neutron flux and control rod positions to calculated signals such as the system change rate. The proposed Purdue Reactor Integrated Machine Learning dataset (PRIMaL), as described in the thesis herein, includes ten signals handpicked to create simple and of various degree of complexity AI/ML benchmarks related directly to the nuclear field, with the goal of kickstarting both a new-founded interest in the nuclear field by AI/ML professionals and building faith in AI/ML amongst nuclear engineers. To the best of our knowledge, PRIMaL is the first curated AI/ML benchmark based on real reactor data and focused on nuclear applications, aiming to advance safety, efficiency, and innovation in the nuclear industry while promoting the responsible and secure use of AI/ML technologies.</p><p>To confirm the validity of the dataset and provide a simple example on how to use the dataset for AI/ML benchmarking, an example problem of classifying shutdown data as gang lowers or SCRAM was performed using three ML algorithms: support vector machine, random forest, and logistic regression. This binary classification problem was repeated 288 times for each algorithm, varying the balance ratio of the SCRAMs to gang lowers, the time prior to the shutdown, and the time after the shutdown the algorithms have access to. The sample problem was a success, as the algorithms were able to distinguish SCRAMs and gang lowers with reasonable accuracy in all cases. Future work would include gathering more data from PUR-1 for the database, as further testing with different sized balanced datasets lead to unusually high accuracy due to the smaller sample size.</p>

<p>The two primarily methodologies discussed in this thesis are the nonparametric entropy-based synthetic timeseries (NEST) and Directed infusion of data (DIOD) algorithms. </p> <p><br></p> <p>The former presents a novel synthetic data algorithm that is shown to outperform sismilar state-of-the-art, including generative networks, in terms of utility and data consistency. Majority of data used are open-source, and are cited where appropriate.</p> <p><br></p> <p>DIOD presents a novel data masking paradigm that presevres the utility, privacy, and efficiency required by the current industrial paradigm, and presents a cheaper alternative to many state-of-the-art. Data used include simulation data (source code cited), equations-based data, and open-source images (cited as needed). </p>