Cette thèse porte sur des limites de grandes cartes à bord aléatoires. Dans un premier temps, nous nous intéressons aux propriétés géométriques de telles cartes. Nous montrons d'abord des résultats concernant les limites d'échelle et les limites locales du bord de cartes de Boltzmann dont le périmètre tend vers l'infini, que nous appliquons à l'étude du modèle O(n) rigide sur les quadrangulations. Ensuite, nous introduisons une famille de quadrangulations du demi-plan aléatoires avec un paramètre de torsion, dont on étudie les limites d'échelle et la structure de branchement. Enfin, nous établissons une propriété de confluence des géodésiques dans les cartes uniformes infinies du demi-plan, qui sont des limites locales de triangulations et quadrangulations à bord uniformes.Dans un second temps, nous considérons des modèles de percolation de Bernoulli sur les cartes uniformes infinies du demi-plan. Nous calculons le seuil de percolation par site critique pour les quadrangulations, et établissons une propriété d'universalité de ces modèles de percolation au point critique à partir des probabilités de croisement. Pour finir, nous étudions la limite locale de grands amas de percolation critiques en construisant l'amas critique émergent, une triangulation uniforme infinie du demi-plan munie d'un amas de percolation critique infini. / This thesis deals with limits of large random planar maps with a boundary. First, we are interested in geometric properties of such maps. We prove scaling and local limit results for the boundary of Boltzmann maps whose perimeter goes to infinity, which we apply to the study of the rigid O(n) loop model on quadrangulations. Next, we introduce a family of random half-planar quadrangulations with a skewness parameter, and study their scaling limits and branching structure. Finally, we establish a confluence property of geodesics in uniform infinite half-planar maps, which are local limits of uniform triangulations and quadrangulations with a boundary.Second, we consider Bernoulli percolation models on uniform infinite half-planar maps. We compute the critical site percolation threshold for quadrangulations, and prove a universality property of these percolation models at criticality involving crossing probabilities. To conclude, we study the local limit of large critical percolation clusters by defining the incipient infinite cluster, a uniform infinite half-planar triangulation equipped with an infinite critical percolation cluster.

Le développement futur des performances sportives est un sujet de mythe et de désaccord entre les experts. Un article, publié en 2004, a donné lieu à un vif débat dans le domaine universitaire [1]. Il suggère que les modèles linéaires peuvent être utilisés pour prédire -sur le long terme- la performance humaine dans les courses de sprint. Des arguments en faveur et en défaveur de cette méthodologie ont été avancés par différent scientifiques et d’autres travaux ont montré que le développement des performances est non linéaire au cours du siècle passé [2, 3]. Une autre étude a également souligné que la performance est liée au contexte économique et géopolitique [4]. Dans ce travail, nous avons étudié les frontières suivantes : le développement temporel des performances dans des disciplines Olympiques et non Olympiques, avec le vieillissement chez les humains et d’autres espèces (lévriers, pur sangs, souris). Nous avons également étudié le développement des performances d’un point de vue plus large en analysant la relation entre performance, durée devie et consommation d’énergie primaire. Nous montrons que tous ces dévelopments sont limitées dans le temps [5, 6, 7] et que les modèles linéaires introduits précédemment sont de mauvais prédicteurs des phénomènes biologiques et physiologiques étudiés. Trois facteurs principaux et directs de la performance sportive sont l’âge [8, 9], la technologie [10, 11] et les conditions climatiques (température) [12]. Cependant, toutes les évolutions observées sont liées au contexte international et à l’utilisation des énergies primaires, ce dernier étant un paramètre indirect du développement de la performance. Nous montrons que lorsque les indicateurs des performances physiologiques et sociétales -tels que la durée de vie et la densité de population- dépendent des énergies primaires, la source d’énergie, la compétitioninter-individuelle et la mobilité sont des paramètres favorisant la réalisation de trajectoires durables sur le long terme. Dans le cas contraire, la grande majorité (98,7%) des trajectoires étudiées atteint une densité de population égale à 0 avant 15 générations, en raison de la dégradation des conditions environnementales et un faible taux de mobilité. Ceci nous a conduit à considérer que, dans le contexte économique turbulent actuel et compte tenu de la crise énergétique à venir, les performances sociétales et physiques ne devraient pas croître continuellement. / The development of sport performances in the future is a subject of myth and disagreement among experts. In particular, an article in 2004 [1] gave rise to a lively debate in the academic field. It stated that linear models can be used to predict human performance in sprint races in a far future. As arguments favoring and opposing such methodology were discussed, other publications empirically showed that the past development of performances followed a non linear trend [2, 3]. Other works, while deeply exploring the conditions leading to world records, highlighted that performance is tied to the economical and geopolitical context [4]. Here we investigated the following human boundaries : development of performances withtime in Olympic and non-Olympic events, development of sport performances with aging among humans and others species (greyhounds, thoroughbreds, mice). Development of performances from a broader point of view (demography & lifespan) in a specific sub-system centered on primary energy were also investigated. We show that all these developments are limited with time [5, 6, 7] and that previously introduced linear models are poor predictors of biological and physiological phenomena. Three major and direct determinants of sport performance are age [8, 9], technology [10, 11] and climatic conditions (temperature) [12]. However, all observed developments are related to the international context including the efficient use of primary energies. This last parameter is a major indirect propeller of performance development. We show that when physiological and societal performance indicators such as lifespan and population density depend on primary energies, the energy source, competition and mobility are key parameters for achieving longterm sustainable trajectories. Otherwise, the vast majority (98.7%) of the studied trajectories reaches 0 before 15 generations, due to the consumption of fossil energy and a low mobility rate. This led us to consider that in the present turbulent economical context and given the upcoming energy crisis, societal and physical performances are not expected to grow continuously.

The goal of the research conducted for this master's thesis is to understand if active thermography is a suitable technique to detect (identify) and measure (approximate depth and or size) defects in additive manufacturing (AM) processes. Although other non-destructive measurement techniques exist, active thermography is an attractive option for AM applications because of the short measurement times that could be implemented between each layer of a print, and because of the relatively inexpensive equipment required. However, pulse thermography is typically applied to detect larger defects (>1 mm) in materials with high thermal conductivity. It was uncertain if active thermography was sensitive enough to detect the small defects (μm) commonly introduced during AM. Defects of this size are common in AM, and their presence significantly impacts the mechanical properties of the final part. For this reason, the detection limits of active thermography in common AM materials were investigated. Numerical models were created to simulate the heat transfer during active thermography in AM structures (polymer and stainless steel) with defects of varying size. The models included non-ideal conditions such as spectral in-depth absorption of the irradiative pulse and free convection from the object's surface. The spectral properties of acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyamide 12 (PA 12) were measured (see chapter 2) and used in the numerical models. The numerical data indicates that active thermography is sensitive enough to detect the existence of defects smaller than 100 μm in AM materials (see chapter 3). Furthermore, it demonstrates that the defect aspect ratio (defect diameter divided by defect depth) for which traditional 1D thermography models may be used to approximate the depth of defects in 3D systems is approximately 6 (see chapter 4). In addition, the depth of defects with lower aspect ratios (~4) may also be approximated with relatively low error (~10% error). Non-ideal systems (those with convection and spectral in-depth absorption) were simulated, and figures are provided which facilitate the approximation of defect depth using simple, ideal thermography models. Active thermography has shown potential as being an efficient technique for detecting and measuring small defects common in AM.

Gedächtnishöchstleistungen sind auch im Alter möglich. Dies konnte am Beispiel der »Methode der Orte« experimentell bestätigt werden. Hierbei hat sich gezeigt, daß das Gehirn über große kognitive Kapazitätsreserven verfügt. In einer speziellen Testmethode (»testing the limits«) zeigt sich aber im Hochleistungsbereich, trotz der grundsätzlichen Plastizität, ein altersbezogenes Nachlassen der Gedächtnismechanik. Offenbar gibt es biologische Grenzen in der Schnelligkeit der menschlichen Vorstellungskraft. Vielleicht gelingt es auf der Grundlage dieser Erkentnnis, einen zuverlässigen Markierungsindikator für das hirnphysiologische Altern zu finden. Daraus könnten sich auch neue Methoden zur Früherkennung von Demenzen ableiten lassen. / A very high level of performance in memory is also possible in old age. This could be confirmed, for example, by experiments using the »method of loci«. It was shown that the human brain has available a large cognitive developmental reserve capacity. Nevertheless, a special method of assessment (»testing the limits«) revealed a robust age related decrease of memory mechanics at the high performance level despite this basic plasticity. Obviously, there are biologic limits of the speed of human imagination. Perhaps it will be possible to find a reliable marker of brainphysiologic aging based on this knowledge. Furthermore, new methods in early detection of dementias might be derived from the approach described.

The development of sport performances in the future is a subject of myth and disagreement among experts. In particular, an article in 2004 [1] gave rise to a lively debate in the academic field. It stated that linear models can be used to predict human performance in sprint races in a far future. As arguments favoring and opposing such methodology were discussed, other publications empirically showed that the past development of performances followed a non linear trend [2, 3]. Other works, while deeply exploring the conditions leading to world records, highlighted that performance is tied to the economical and geopolitical context [4]. Here we investigated the following human boundaries : development of performances withtime in Olympic and non-Olympic events, development of sport performances with aging among humans and others species (greyhounds, thoroughbreds, mice). Development of performances from a broader point of view (demography & lifespan) in a specific sub-system centered on primary energy were also investigated. We show that all these developments are limited with time [5, 6, 7] and that previously introduced linear models are poor predictors of biological and physiological phenomena. Three major and direct determinants of sport performance are age [8, 9], technology [10, 11] and climatic conditions (temperature) [12]. However, all observed developments are related to the international context including the efficient use of primary energies. This last parameter is a major indirect propeller of performance development. We show that when physiological and societal performance indicators such as lifespan and population density depend on primary energies, the energy source, competition and mobility are key parameters for achieving longterm sustainable trajectories. Otherwise, the vast majority (98.7%) of the studied trajectories reaches 0 before 15 generations, due to the consumption of fossil energy and a low mobility rate. This led us to consider that in the present turbulent economical context and given the upcoming energy crisis, societal and physical performances are not expected to grow continuously.

Limits erleichtern die Klassifizierung harmonischer Strukturen als Netzwerke arithmetischer Beziehungen innerhalb der Grenzen bestimmter Primzahl-Faktoren. Die Theorie der Limits in mikrotonaler Musik geht auf Harry Partch zurück. Ben Johnston entwickelte sie weiter und schuf die erste Notationsmethode in erweiterter reiner Stimmung. Primzahl-Faktoren lassen sich wie räumliche Dimensionen vorstellen und (vergleichbar mit Leonhard Eulers und Hugo Riemanns Tonnetzen) geometrisch abbilden. Gemäß dieser Anschauung beruht die traditionelle Terzharmonik (über die Oktav hinaus) auf zwei Primfaktoren (3, 5) und entsprechend können alle ihre Zusammenhänge in einem Koordinatensystem dargestellt werden, in welchem jeder Ton auf der x- und der y-Achse, sozusagen zweidimensional, erscheint. Eine Erhöhung des Limits (d. h. wenn Intervalle aus höheren Limits hinzutreten) erfordert zusätzliche Dimensionen. Über die bloße Hinzurechnung neuer Intervallgrößen hinaus scheint jedes Limit charakteristische Tendenzen und Bedingungen zu entfalten. Mein Ziel ist, die erweiterte reine Stimmung auf Funktionen hin zu untersuchen, die sich mit denen herkömmlicher tonaler Musik (Limit 5) vergleichen lassen. Meine Analyse widmet sich demgemäß Prinzipien harmonischer Verwandlung – Auflösung, Spannung, Modulation etc. – und ihrem Einsatz im Bestreben, großformale Strukturabläufe zu überspannen. Im Vergleich zur Terzharmonik (Limit 5) werde ich nur ein einziges Limit höher ansetzen und, in der beschränkten Versuchsanordnung eines dreistimmigen Kontrapunkts, einfache Kadenzformeln bestimmen. Alles, was ich im Rahmen meines Experiments vorschlagen möchte, sind Voraussetzungen einer umfassenderen Harmonielehre im Limit 7. / Limits are a way to categorise harmonic structures as networks of arithmetic relationships within the boundaries of specific prime factors. In microtonal music, the theory of limits was introduced by Harry Partch and further developed by Ben Johnston who invented the first method of notation in extended just intonation. Prime factors may be imagined as something similar to spatial dimensions and depicted geometrically, such as in Leonhard Euler’s and Hugo Riemann’s lattices. For example, if (in addition to the octave) traditional thirds-harmony involves two prime factors (3, 5), all of its relationships can be drawn into a coordinate system where the notes figure both on the x- and y-axis, in two dimensions so to speak. Each higher limit would, thus, require an additional dimension (provided that intervals in the respective higher limits occur). Far from simply adding new interval sizes, it seems that every limit unfolds characteristic tendencies and constraints. My objective is to explore extended just intonation by means of functions very similar to those of 5-limit tonality. Accordingly, my analysis focuses on principles of harmonic transformation – resolution, suspension, modulation, etc. – and its application in the quest to overarch large-form development. Compared to conventional tonal music (limit 5), I will step up by only one additional limit, using a restrictive three-voice setup to determine basic cadential formulas. All I intend to propose within the scope of an experiment are prerequisites to a more comprehensive treatise of 7-limit harmony.

The ever-changing industrial processes which are becoming more globalised as well as the merging of markets in different economies, led to an increased focus on the health and safety of workers in the industries and the mining sector over the past decades. Occupational exposure limits (OELs) have been used for more than half a century as a risk management tool for the prevention of work-related illnesses which may arise from the exposure to a wide variety of hazardous chemical substances in the working environment. Aim: The aim of this study is to analyse comparatively occupational exposure limits (OELs) of hazardous chemical substances from selected groups contained in the Hazardous Chemical Substance Regulations (HCSR) and the Mine Health and Safety Regulations (MHSR) with those of selected developed countries and organisations. Method: The two lists of OELs from South Africa – HCSR and MHSR – were compared with 11 different developed countries and/or organisations namely: Canada (British Colombia), United Kingdom (Health and Safety Executive, HSE), Australia (National Occupational Health and Safety Commission, NOHSC), New Zealand (Ministry of Business, Innovation and Employment), Japan (Japan Society for Occupational Health, JSOH), Finland (Ministry of Social Affairs and Health), Germany (Deutsche Forschungsgemeinschaft-DFG), Sweden (Swedish Work Environment Authority) and United States of America (American Conference of Governmental Industrial Hygienists, ACGIH, Occupational Safety and Health Administration, OSHA and National Institute for Occupational Safety and Health, NIOSH). The selection of these countries and organisations was done on the basis of their dominance in the literature as well as the availability of the lists containing OELs. The OELs from each country and/or organisation, depending on the nature and characteristics of the said element and/or compound, were categorised into one of four groups, namely: pesticides, metals, dusts and fibres. The geometric means of each country and/or organisation were calculated from the ratios of each list by using the HCSR and MHSR as the denominator respectively. Results: It became evident that South Africa performed poorly when compared to other countries and/or organisations, indicated in this study. OSHA overall had the highest set OELs, in five out of the six comparisons that could be made, thus being less stringent than South Africa’s. Countries and organisations such as Sweden, Japan and Finland have the lowest overall set OELs for the different groups respectively. Conclusion: South African OELs legislated by both the HCSR and MHSR, are overall higher (less stringent) when compared to those of developed countries and/or organisations. The less stringent nature of South African OELs may be attributed to infrequent rate at which they are updated. The failure to incorporate recent scientific knowledge into OELs may impact on the health of workers. South Africa should follow international best practice and increase the frequency at which OELs are updated. Recommendations: The effectiveness of having two sets of OELs within a country; each applicable to its own industry should be investigated. Attention with regards to the groups lacking attention, i.e. fibres and pesticides should be given priority when revised. Although the other groups should not be disregarded. Duplicate OELs identified in the HCSR should be removed. To prevent duplicate OELs from being established it would be prudent to utilise CAS numbers when referring to substances in addition to their common and chemical names, thus this supports the recommendations made in an earlier study. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015

The ever-changing industrial processes which are becoming more globalised as well as the merging of markets in different economies, led to an increased focus on the health and safety of workers in the industries and the mining sector over the past decades. Occupational exposure limits (OELs) have been used for more than half a century as a risk management tool for the prevention of work-related illnesses which may arise from the exposure to a wide variety of hazardous chemical substances in the working environment. Aim: The aim of this study is to analyse comparatively occupational exposure limits (OELs) of hazardous chemical substances from selected groups contained in the Hazardous Chemical Substance Regulations (HCSR) and the Mine Health and Safety Regulations (MHSR) with those of selected developed countries and organisations. Method: The two lists of OELs from South Africa – HCSR and MHSR – were compared with 11 different developed countries and/or organisations namely: Canada (British Colombia), United Kingdom (Health and Safety Executive, HSE), Australia (National Occupational Health and Safety Commission, NOHSC), New Zealand (Ministry of Business, Innovation and Employment), Japan (Japan Society for Occupational Health, JSOH), Finland (Ministry of Social Affairs and Health), Germany (Deutsche Forschungsgemeinschaft-DFG), Sweden (Swedish Work Environment Authority) and United States of America (American Conference of Governmental Industrial Hygienists, ACGIH, Occupational Safety and Health Administration, OSHA and National Institute for Occupational Safety and Health, NIOSH). The selection of these countries and organisations was done on the basis of their dominance in the literature as well as the availability of the lists containing OELs. The OELs from each country and/or organisation, depending on the nature and characteristics of the said element and/or compound, were categorised into one of four groups, namely: pesticides, metals, dusts and fibres. The geometric means of each country and/or organisation were calculated from the ratios of each list by using the HCSR and MHSR as the denominator respectively. Results: It became evident that South Africa performed poorly when compared to other countries and/or organisations, indicated in this study. OSHA overall had the highest set OELs, in five out of the six comparisons that could be made, thus being less stringent than South Africa’s. Countries and organisations such as Sweden, Japan and Finland have the lowest overall set OELs for the different groups respectively. Conclusion: South African OELs legislated by both the HCSR and MHSR, are overall higher (less stringent) when compared to those of developed countries and/or organisations. The less stringent nature of South African OELs may be attributed to infrequent rate at which they are updated. The failure to incorporate recent scientific knowledge into OELs may impact on the health of workers. South Africa should follow international best practice and increase the frequency at which OELs are updated. Recommendations: The effectiveness of having two sets of OELs within a country; each applicable to its own industry should be investigated. Attention with regards to the groups lacking attention, i.e. fibres and pesticides should be given priority when revised. Although the other groups should not be disregarded. Duplicate OELs identified in the HCSR should be removed. To prevent duplicate OELs from being established it would be prudent to utilise CAS numbers when referring to substances in addition to their common and chemical names, thus this supports the recommendations made in an earlier study. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2015

The Walk for a Day trail will pass over land, the Water Quality Protection Lands, established to protect the sensitive karst aquifer. The trail requires specific management due to the sensitive nature of the karst landscape. This paper explores access management techniques and case studies to develop recommendations for management of the Walk for a Day trail. This paper concludes that by utilizing techniques such as Limits of Acceptable Change and spatial management strategies, and encouraging strong stakeholder participation it is possible to develop a recreational trail on sensitive public land. / text

<p>Chile and Santiago are struggling with heavy environmental problems as a consequence of urbanisation and industrialisation. In the Santiago region the air is seriously contaminated and most of the rivers are classified as heavily polluted.</p><p>The aim of this thesis is to survey the industrial fluid waste situation in the Santiago region and to make suggestions on technological improvements or process changes. The purpose is also to study five different enterprises more closely and to give more detailed suggestions for improvement. Another purpose is to summarize relevant Chilean legislation.</p><p>Information, provided by the supervisory authority, about the release of industrial wastewater to rivers has been analysed. Deep interviews have been made with authorities and consultants. Five enterprises have been visited; a brewery, a dairy, a bakery, a producer of cooked meat and a surface treatment industry. The present treatment of the wastewater was studied at the plants and the information was completed with a questionnaire to the responsible at each company.</p><p>The contamination load released to the Chilean rivers is heavy. The rivers in southern Chile receive the biggest loads of BOD and SS and the rivers in central Chile were the most exposed to discharges of the metals Cr, Cu, Zn and CN as well as phenols.</p><p>The industrial discharge into the rivers of Santiago RM and Region VII is also to a large extent characterized by high concentrations of BOD and SS. Large releases of oils and greases, nitrogen and phosphorus are also fairly common, as are too high or too low pH levels. The food industry is the most contaminating sector, but also tanneries have great problems with effluents exceeding limits.</p><p>All five companies visited share the need to take measures towards more water saving technologies. The brewery, the producer of cooked meat and the surface treatment company also need end-of-pipe-treatment of their wastewater. In many cases, the recommended and most economic alternative is to separate the flows with the highest concentration of polluting substances for internal treatment, while releasing the rest of the wastewater to the outside sewage system. The costs of the suggested changes must be balanced against the present costs for treatment of wastewater and remaining solid waste as well as the costs for alternative treatments.</p><p>The economic incentives for Chilean companies to invest in wastewater treatment plants or to optimize the processes until today have been few. Cost reductions may be achieved by savings in water consumption and reuse of raw material. Another motive could be to keep “one step ahead” if the discharge limits in the future are tightened up leading to rising costs.</p> / <p>Chile och Santiago brottas med omfattande miljöproblem till följd av urbanisering och industrialisering. I santiagoregionen är luftföroreningarna svåra och de flesta floderna klassas som gravt förorenade av CONAMA, det chilenska naturvårdsverket.</p><p>Syftet med examensarbetet är att kartlägga situationen i santiagoregionen med avseende på industriell avloppsrening samt att ge förslag på förbättring av teknik eller förändring av processer. Dessutom är syftet att studera fem industrier närmare och att ge mer detaljerade förslag på åtgärder. Syftet är också att ge rekommendationer för fortsatt utveckling av relevant chilensk lagstiftning.</p><p>Uppgifter från tillsynsmyndigheten för utsläpp till ytvattendrag har studerats och djupintervjuer har gjorts med myndigheter och konsulter. Fem olika industrier besöktes; ett bryggeri, ett mejeri, ett bageri, ett charkuteri samt en ytbehandlingsindustri. Nuvarande hantering av processvattnet studerades på plats och med hjälp av ett frågeformulär kompletterades uppgifterna av ansvariga på företagen.</p><p>Föroreningsbelastningen på Chiles floder är stor. Floderna i södra delen av landet tar emot störst mängder organiskt material och suspenderat material medan centrala Chiles floder är värst drabbade av utsläpp av metallerna Cr, Cu, Zn och CN samt utsläpp av fenoler. Utsläppen från industrin till floderna i Region Metropolitana och Region VII kännetecknas också i stor utsträckning av höga halter BOD och suspenderat material. Relativt vanligt är också stora utsläpp av oljor och fetter, kväve, fosfor samt för höga eller låga för pH-värden. Det är främst flera olika typer av livsmedelsindustri, som har de största utsläppen till floderna, men även garverierna har stora problem med överskridande av gränsvärden.</p><p>Gemensamt för de fem besökta företagen är att vattenbesparande åtgärder bör vidtas för att minska volymen avloppsvatten som går till extern eller intern behandling. Bryggeriet, charkuterifabriken och ytbehandlaren behöver även end-of-pipe-rening. Det kan ofta vara lämpligt och mer ekonomiskt att avskilja de flöden som har högst halt av föroreningar till den interna reningsanläggningen. Resten av avloppet kan i vissa fall släppas ut på avloppsnätet. Kostnader för föreslagna åtgärder måste vägas mot aktuella kostnader för behandling av avlopp och restprodukter, samt kostnader för alternativa behandlingar.</p><p>Incitamenten, bl a de ekonomiska, för chilenska företag att skaffa eget reningsverk eller att resurseffektivisera produktionen har hittills varit små. Kostnadsminskningar kan uppnås genom sänkt vattenförbrukning samt återanvändning av råmaterial. Ytterligare en drivkraft kan vara att ”ligga steget före” om utsläppskraven i framtiden skärps och kostnaderna därmed ökar.</p>