Made available in DSpace on 2016-12-12T20:25:12Z (GMT). No. of bitstreams: 1 Everton Ruggeri.pdf: 24321266 bytes, checksum: d9116328281ce8d4d01d557335e3d70b (MD5) Previous issue date: 2014-09-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years, the study of chatter vibrations has been intensifying in the machining of materials, however, the analysis of chatter vibration has been conducted only for machining of ductile materials and few studies analyzing these vibrations in machining of brittle materials are found in the literature. The chatter vibrations in machining process can considerably compromise the workpiece surface finish, tool wear and in some cases provide severe damage to the machine-tool. Thus there is an imminent need to expand the theory of chatter vibrations for the class of brittle materials. To analyze the vibrations of the process and zones where the process is stable, and where it is unstable, the stability lobes diagram was used. This diagram is constructed in most cases for applications at high speed cutting. In this work, the analysis of the stability lobe diagram was made for application at low cutting speed, where the phenomenon of damping arises. The damping is a crucial factor in the process, it increases system stability. The phenomenon of damping was considered in the formulation of chatter vibrations using the indentation model of Wu. Apart from consideration of the damping effect, an analysis of dynamic stiffness on the mechanical system adopted was made by means of a simulation using the peak to peak method of passing of the tool in the workpiece. For experiments validations, the signals of force and acceleration were acquired and an analysis was conducted in time and frequency domain to identify where the vibrations emerged. The workpiece surface finish and RMS value of the signals were checked and compared with the stability conditions of the process. The results demonstrated perfectly the consequences that the chatter vibrations present in machining of grey cast iron and proved that the stability lobe diagram shows good results to detect the vibrations in machining of brittle materials, determining the areas where the material removal should be avoid. / Nos últimos anos, o estudo das vibrações regenerativas tem-se intensificando na usinagem de materiais, entretanto, a análise das vibrações regenerativas vem sendo conduzidas apenas para a usinagem de materiais dúcteis e poucos trabalhos analisando essas vibrações na usinagem de materiais frágeis são encontrados na literatura. As vibrações regenerativas no processo de usinagem podem comprometer consideravelmente o acabamento superficial da peça, o desgaste da ferramenta e em alguns casos proporcionar danos severos à máquina-ferramenta. Por isso, há uma necessidade eminente de expandir a teoria das vibrações regenerativas para a classe de materiais frágeis. Para analisar as vibrações no processo e regiões onde se possui um corte estável e onde há um corte instável, foi utilizado o diagrama de lóbulos de estabilidade. Este diagrama é construído na grande maioria dos casos para aplicações em alta velocidade de corte. Neste trabalho, a análise do diagrama de lóbulos de estabilidade foi feita para ensaios em baixa velocidade de corte, onde o fenômeno de amortecimento surge. O amortecimento é um fator crucial no processo, pois aumenta a estabilidade do sistema. O fenômeno de amortecimento foi considerado na formulação das vibrações regenerativas utilizando o modelo de indentação de Wu. Além da consideração do amortecimento, uma análise da influência da rigidez no sistema mecânico adotado foi realizada por uma simulação utilizando o método pico a pico, da passagem da ferramenta no corpo de prova. Para validação dos experimentos realizados, os sinais de força e de aceleração foram adquiridos e uma análise foi conduzida no domínio do tempo e no domínio da frequência para identificar onde as vibrações surgiram. O acabamento superficial da peça e valor RMS dos sinais também foram verificados e comparados com as condições de estabilidade do processo. Os resultados demonstraram perfeitamente as consequências que as vibrações regenerativas apresentam na usinagem do ferro fundido cinzento e comprovam que o diagrama de lóbulos de estabilidade mostra bons resultados para identificação das vibrações na usinagem de materiais frágeis, determinando as zonas onde se deve evitar a remoção de material.

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O medo e a ansiedade são emoções que apresentam claro valor adaptativo, e que tem suas origens nas reações de defesa que os animais exibem em resposta a situações de ameaça que podem comprometer sua integridade física ou sobrevivência. Recentes estudos têm indicado que a matéria cinzenta periaquedutal dorsal (MCPD) está envolvida na organização e expressão de comportamentos intempestivos do tipo fuga e luta, os quais são relacionados ao estado de medo, e também participa, juntamente com estruturas prosencefálicas (ex. córtex pré-frontal, sistema septo-hipocampal e amígdala), do controle de comportamentos defensivos mais elaborados e orientados relacionados à ansiedade. O presente estudo investigou a participação da MCPD na modulação de diferentes comportamentos defensivos (p. ex. fuga, esquiva e avaliação de risco) induzidos por métodos artificial (estimulação química) e naturalístico (exposição ao predador) em camundongos. Na primeira etapa, investigamos o padrão de resposta comportamental induzida pela infusão do ácido D,L-homocistéico (DLH, estímulo aversivo químico) na MCPD em diferentes situações ou ambientes, com e sem grande disponibilidade de espaço - o Mouse Defense Test Battery (MDTB) e a Arena (Experimento 1), respectivamente. Além disso, o presente estudo avaliou a habilidade dos animais de reagirem a estímulos aversivos (predador) durante o período inicial (nos 60 s iniciais) do efeito do ácido DLH (fuga explosiva) (Experimento 3), e imediatamente após esse período, no qual o animal apresente comportamento de congelamento ou imobilidade (Experimento 2). Nossos resultados indicaram que a fuga desencadeada pela estimulação química é a resposta predominante de camundongos e que sua exibição depende da disponibilidade de espaço, uma vez que a maioria dos saltos observados na arena está intimamente relacionada ao contato tátil do animal com as paredes do aparato. Esse perfil de respostas de fuga explosiva e saltos parece não representar o padrão comportamental defensivo natural, tal como acontece diante de uma ameaça proximal (ex. um predador), uma vez que durante a estimulação química os camundongos apresentaram um déficit na estratégia antipredador. A segunda etapa do estudo avaliou os efeitos da injeção intra-MCPD do agonista glutamatérgico ácido N-metil-D-aspártico (NMDA), do inibidor da enzima de síntese do óxido nítrico neuronial (NOSn), N?-propil-L-arginina (NPLA) (Experimento 4), e do agonista não seletivo de receptores do fator de liberação de corticotrofina (CRF), CRF ovino (oCRF) (Experimento 5), no comportamento defensivo de camundongos submetidos ao MDTB e ao teste de exposição ao rato (Rat Exposure Test; RET). Os resultados da segunda etapa demonstraram que a ativação de receptores NMDA na MCPD de camundongos intensifica comportamentos relacionados à esquiva do predador. De maneira interessante, essas alterações produzidas pelo NMDA foram consistentemente revertidas pelo inibidor da NOSn, previamente microinjetado no mesmo sítio. Além disso, efeitos intrínsecos do NPLA atenuaram as respostas de esquiva e de avaliação de risco em camundongos submetidos ao RET. Por fim, os resultados da segunda etapa também apontaram para um efeito proaversivo (nas respostas de salto e de esquiva) do agonista de receptores CRF, indicando uma participação dos sistemas glutamatérgico, nitrérgico e CRFérgico, localizados na MCPD, na modulação de diferentes estratégias defensivas (ex. esquiva, avaliação de risco e saltos) de camundongos submetidos ao confronto com o predador. Em conjunto, nossos resultados corroboram a hipótese de que a MPCD está envolvida tanto na organização e expressão de comportamentos intempestivos do tipo fuga e luta como também no controle de comportamentos defensivos mais elaborados e orientados, tais como a avaliação de risco e a esquiva. / The midbrain dorsal periaqueductal grey (DPAG) is part of the brain defensive system involved in active defense reactions to threatening stimuli. Many lines of evidence suggest that besides fundamentally controlling fear-like responses (fight and flight) the DPAG also controls responses related to anxiety, such as avoidance and risk assessment. This study investigated the role of DPAG on different defensive strategies (i.e. flight, avoidance and risk assessment) elicited by artificial (chemical stimulation, Experiments 1-3) and naturalistic (exposure to predator, Experiments 4 and 5) paradigms in mice. Firstly, D,L-Homocysteic acid (DLH) was infused into the DPAG and behavioral responses of mice were evaluated in two different situations, a rectangular novel chamber and a large oval runway, the Mouse Defense Test Battery (MDTB) apparatus (Exp. 1). We also investigated the ability of mice to react to a threatening stimulus (ex. a predator) during (Exp. 3) and immediately after (Exp. 2) the hyperactive responses (ex. jumping and running) induced by DLH injection. Our results indicated that running as opposed to jumping is the primary response in mice injected with DLH into the DPAG when the environment enables flight. However, mice did not react the predator during the flight reaction induced by chemical stimulation, suggesting the behavioral profile induced by DLH infusion into the DPAG is not related to a normal antipredator flight. In the Experiments 4 and 5, we evaluated the effects of three different compounds, N-methyl-D-Aspartate (NMDA), a NMDA receptor agonist, N?-propyl-L-arginine (NPLA), an neuronal nitric oxide synthase (nNOS) inhibitor as well as ovine CRF (oCRF), a nonspecific corticotropin-releasing factor (CRF) receptor agonist, injected into the DPAG of mice, in two predator-stress situations, the Mouse Defense Test Battery (MDTB), and the Rat Exposure Test (RET). Firstly, our results demonstrated that NMDA receptor activation into the mouse DPAG enhances antipredator reactivity (avoidance), an effect that was attenuated by prior infusion of NPLA into the same site. Moreover, the results from the Experiment 4 indicated that the NPLA treatment per se induces consistent anti-aversive effects on defensive behaviors (avoidance and risk assessment) of mice confronted by predator. Finally, our results pointed out a proaversive effect (e.g. increased jump escapes and avoidance behaviors) following intra-DPAG infusion of oCRF, suggesting an important role of glutamatergic, nitrergic and CRFergic systems into the DPAG on the defensive behaviors (risk assessment, avoidance and jumps) elicited by the confront to the predator. Taken together, present results are compatible with previous studies which have emphasized the role of the periaqueductal gray in the modulation of behavioral responses related to anxiety such as risk assessment and avoidance besides fundamentally controlling fear-like responses.

Botrytis and Anthracnose fruit rots, caused by Botrytis cinerea and Colletotrichum spp., respectively, are major strawberry diseases. This study aimed to compare organic and conventional strawberry production systems by evaluating the sensitivity of B. cinerea and Colletotrichum spp. isolates to the main single-site fungicides used in Brazil and by characterizing the spatial and temporal dynamics of the diseases caused by these pathogens using epidemiological tools. Isolates were collected from conventional and organic fields in four different Brazilian states from 2013 to 2015. Resistance to azoxystrobin, iprodione and thiophanate-methyl was found in B. cinerea isolates with EC50 values higher than 71.9, 688 and 1.2 μg/ml, respectively. Resistance to the aforementioned fungicides was observed in 87.5, 76.6 and 92.2 % of isolates from conventional fields, and 31.4, 22.9 and 51.4 % of isolates from organic fields, respectively. Moreover, frequencies of populations with multiple fungicide resistance to the three active ingredients were 75 and 8.6 %, with no resistance to any of the fungicides were 6.25 and 34.3 % for isolates collected from conventional and organic areas, respectively. Molecular analyses of the cytochrome b, beta-tubulin and bos1 genes revealed, respectively, the presence of G143A, E198A and I365N/S, Q369P or N373S mutations in resistant populations of B. cinerea. Fungicides sprayed preventively on strawberry fruit inoculated with B. cinerea failed to control resistant isolates. Isolates of C. acutatum resistant to azoxystrobin and difenoconazole were not observed. Mean EC50 values for isolates collected from organic fields were 0.44 and 0.95 μg/ml, and from conventional areas were 0.629 and 0.107 μg/ml for azoxystrobin and difenoconazole, respectively. Populations of C. acutatum showed insensitivity to thiophanate-methyl rather than resistance and EC50 values could not be determined. None of the isolates contained the most common mutations associated with fungicide resistance. The temporal and spatial dynamics of Botrytis and Anthracnose fruit rots were characterized in the 2015 strawberry season in conventional and organic farms. Temporal progress models were fitted to the cumulative incidence of diseased strawberry fruit or plants over time with non-linear regressions. The spatial pattern of the diseases was analyzed according to the index of dispersion (D), the index of aggregation (V/M), and the Taylor\'s power law. The incidence-diseased fruit density relationship was analyzed by fitting a linear model. Fruit with symptoms of Colletotrichum spp. were not observed in the organic area and were found in few assessment dates in the conventional area. Incidence of Botrytis fruit rot in symptomatic fruit and plants were generally well described by the logistic model. The organic area presented disease incidence and daily progress rate higher than the conventional area. The aggregation of diseased fruit on strawberry plants were observed for both areas. Botrytis fruit rot presented similar epidemiological patterns for both conventional and organic areas, however, disease intensity was greater for the organic area; this was likely due to differences in disease control management. This study reinforces the importance for the implementation of integrated management programs in strawberry nurseries and production fields. / Mofo cinzento e antracnose do fruto, causados por Botrytis cinerea e Colletotrichum spp., respectivamente, são as mais importantes doenças em morangueiro. Esse estudo objetivou comparar sistemas de produção orgânico e convencional em morangueiro através da avaliação da sensibilidade de isolados de B. cinerea e Colletotrichum spp. aos principais fungicidas sítio-específicos utilizados no Brasil, e da caracterização das dinâmicas espacial e temporal das doenças com o uso de ferramentas epidemiológicas. Isolados foram coletados em campos convencionais e orgânicos em quatro diferentes Estados brasileiros nos anos de 2013 a 2015. Resistência à azoxistrobina, iprodiona e tiofanato-metílico foi encontrada em isolados de B. cinerea com valores de CE50 maiores que 71,9, 688 and 1,2 μg/ml, respectivamente. Resistência aos fungicidas acima mencionados foi observada em 87,5, 76,6 and 92,2 % dos isolados provenientes de campos convencionais e em 31,4, 22,9 and 51,4 % dos isolados oriundos de campos orgânicos, respectivamente. Além do mais, frequências de populações com resistência múltipla aos três fungicidas foram 75 e 8,6 %; e com nenhuma resistência a qualquer dos produtos, 6,25 e 34,3 % para isolados coletados em campos convencionais e orgânicos, respectivamente. Análise molecular dos genes do citocromo b, beta-tubulina e bos1 revelaram, respectivamente, a presença das mutações G143A, E198A e I365N/S, Q369P ou N373S em populações resistentes. Fungicidas aplicados preventivamente em morangos inoculados com B. cinerea falharam em controlar isolados resistentes. Isolados de C. acutatum resistentes à azoxistrobina e ao difenoconazole não foram observados. Valores médios de CE50 para isolados coletados em campos orgânicos foram 0,44 e 0,95 μg/ml; e para isolados de áreas convencionais, 0,629 e 0,107 μg/ml para azoxistrobina e difenoconazole, respectivamente. Populações de C. acutatum demonstraram insensibilidade ao tiofanato-metílico e valores de CE50 não puderam ser determinados. Nenhum dos isolados analisados continha as mutações comumente associadas à resistência a fungicidas. As dinâmicas temporal e espacial das doenclas causadas por esses patógenos foram caracterizadas na safra de 2015 em campos de morangueiro convencional e orgânico. Modelos de progresso temporal foram ajustados à incidência cumulativa de frutos ou plantas doentes no tempo com regressões não-lineares. O padrão espacial das doenças foi analisado de acordo com o índice de dispersão (D), índice de agregação (V/M) e lei de Taylor. A relação incidência-densidade de frutos doentes foi analisada com o ajuste de um modelo linear. Frutos com sintomas de Colletotrichum spp. não foram observados na área orgânica e foram encontrados em poucos dias de avaliação na área convencional. Incidência de mofo cinzento em frutos e plantas foi bem descrita pelo modelo logístico. A área orgânica apresentou incidência de doença e taxa de progresso diária maiores que da área convencional. A agregação de frutos doentes em plantas foi observada para ambos os locais. O mofo cinzento apresentou padrões epidemiológicos semelhantes para as áreas convencional e orgância, porém com maior intensidade de doença no campo orgânico, provavelmente em decorrência do manejo adotado para controle de doenças. Esse estudo reforça a importância da implementação de programas de manejo integrado de doenças em viveiros de mudas e campos de produção de morangueiro.

Stricter emission legislation for heavy trucks in combination with the customers demand on low fuel consumption has resulted in intensive technical development of engines and their control systems. To control all these new solutions it is desirable to have reliable models for important control variables. One of them is the air mass-flow, which is important when controlling the amount of recirculated exhaust gases in the EGR system and to make sure that the air to fuel ratio is correct in the cylinders. The purpose with this thesis was to use system identification theory to develop a model for the air mass-flow through the compressor. First linear black-box models were developed without any knowledge of the physics behind. The collected data was preprocessed to work in the modeling procedure and then models with one or more inputs where built according to the ARX model structure. To further improve the models performance, non-linear regressors was developed from physical relations for the air mass-flow and used to form grey-box models of the air mass-flow.In conclusion, the performance was evaluated through comparing the estimated air mass-flow from the best model with the estimate that an extended Kalman filter together with a physical model produced. / Hårdare utsläppskrav för tunga lastbilar i kombination med kundernas efterfrågan på låg bränsleförbrukning har resulterat i en intensiv utveckling av motorer och deras kontrollsystem. För att kunna styra alla dessa nya lösningar är det nödvändigt att ha tillförlitliga modeller över viktiga kontrollvariabler. En av dessa är luftmassflödet som är viktig när man ska kontrollera den mängd avgaser som återcirkuleras i EGR-systemet och för att se till att kvoten mellan luft och bränsle är korrekt i motorns cylindrar. Syftet med det här examensarbetet var att använda systemidentifiering för att ta fram en modell över luftmassflödet förbi kompressorn. Först togs linjära svartboxmodeller fram utan att ta med någon kunskap om den bakomliggande fysiken. Insamlade data förbehandlades för att passa in i modelleringsproceduren och efter det skapades i enlighet med ARX-modellstrukturen modeller med en eller flera insignaler. För att ytterligare förbättra modellernas prestanda togs icke-linjära regressorer fram med hjälp av fysikaliska relationer för luftmassflödet. Dessa användes sedan för att skapa gråboxmodeller av luftmassflödet. Avslutningsvis utvärderades prestandan genom att det estimerade luftmassflödet från den bästa modellen jämfördes med det estimat som ett utökat kalmanfilter tillsammans med fysikaliska ekvationer genererade.

Stora mängder energi lämnar bostäder med avloppsvattnet utan något bemödande att återföra det uppvärmda vattnets värmeenergi tillbaka till byggnaden. Med ökade klimatskalsförbättringar av traditionellt slag för att möta de nära-nollenergikrav på nybyggnationer för bostadshus som träder i kraft i slutet av 2020 kan energiförlusterna i byggnader till allt större del allokeras till det avloppsvatten som lämnar byggnaden. Målet med detta arbete är att undersöka huruvida betydande energibesparingar inom området kan erhållas, samt att bedöma de ekonomiska möjligheterna och utsikterna för att tillvarata värmeenergi med hjälp av värmepump ur gråvatten från  flerbostadshus uppkopplade mot fjärrvärmenät. Och i och med det visa vilka faktorer som visar sig utöva påverkan på de driftmässiga besparingsmöjligheterna samt uppvisa hur pass känsligt resultatet är i förhållande till ett urval av dessa faktorer. Arbetet utgörs av och har genomförts i två delar: en litteraturstudie och en beräkningsstudie. Avloppsvatten kan delas in i spillvatten, dagvatten och dräneringsvatten. Spillvatten är avfallsbidraget från hushåll och andra fastigheter till avloppet. Hushållens spillvatten kan i sin tur indelas i gråvatten och svartvatten. Gråvatten är det vatten som kommer från bad, disk och tvätt, vilket av det skälet även kallas BDT-vatten. Svartvatten är det vatten som spolas ut från toaletter, och kallas därför även klosettvatten. Vid separerade flöden infinner sig möjligheten att tillvarata värmeenergi direkt från gråvatten, som också är den varmare, volymmässigt största och mer lätthanterliga fraktionen, både ur vattenrenings- och värmeåtervinningssynpunkt. Studier på källsorterande system visar på flera fördelar i stort med att hålla hushållens avloppsflöde separerade, såsom bland annat utökad resurseffektivitet av kväve och fosfor vid reningsverken. Nedsmutsning av värmeväxlarytor, i synnerhet av biofilm, utgör en utmaning då avloppsvatten ska användas som värmekälla och är något som måste beaktas även vid tillvaratagande av värme ur gråvatten. Resultatet från beräkningsstudien av ett enskilt fall med tappvarmvattenförvärmning, givet en rad antaganden, gav en driftmässig kostnadsbesparing på cirka 31 000 kr per år och ett nuvärde på dessa årliga besparingar sett över 20 år på cirka 355 000 kr. Energibesparingen uppgick till cirka 63 000 kWh per år vilket innebär en minskning av totala behovet av köpt energi för tappvarmvattenproduktion med cirka 67 % vid uppvärmning av tappvarmvatten till 55 °C. Känslighetsanalysen visar att avgörande parametrar i beräkningsstudien såsom el- och fjärrvärmepris, värmepumpens livslängd och kalkylräntan medför relativt stora förändringar av resultatet om de tillåts att variera. Det är uppenbart att det finns stora mängder energi att återvinna, det är också uppenbart att svårigheter gör att gråvatten som värmekälla inte kan behandlas lättvindigt då bland annat den långsiktiga utvecklingen av vattenanvändningen och hög föroreningsgrad är faktorer som måste beaktas i tillägg till de faktorer som tas upp i känslighetsanalysen. Dubbla system med fjärrvärme och värmepump innebär en högre investering men är samtidigt något som kan ses som ett verktyg för att utnyttja de ökande energiprisvariationer som en allt större andel förnybar icke-reglerbar elproduktion sannolikt innebär genom att helt enkelt kunna variera uppvärmningssätt efter varierande energipriser och finna optimal andelsfördelning. För en fastighetsägare blir det i takt med en sådan utveckling alltmer gynnsamt att kunna välja det som för tiden är det billigaste alternativet. / Large amounts of energy leave homes with wastewater without any effort to return the heated water's thermal energy back to the building. With increased thermal envelope improvements of a traditional nature to meet the nearly zero-energy requirements for residential buildings that will come into effect by the end of 2020, energy losses in buildings can increasingly be allocated to the wastewater leaving the building. The aim of this work is to investigate whether significant energy savings in the mentioned area can be obtained, as well as to assess the economic opportunities and prospects for utilizing heat energy from grey water from multi-residential buildings connected to district heating networks with the help of a heat pump. And by that show which factors are shown to influence the operational savings and how sensitive the results are in relation to a selection of these factors. The work consists of and has been carried out in two parts: a literature study and a calculation study. Household wastewater can be divided into grey and black water. Grey water is the water that comes from bath, dishes and laundry and black water is the water that is flushed out of the toilets. Separated flows reveal the possibility of utilizing thermal energy directly from grey water, which is also the warmer, volume largest and more manageable fraction, both from a water purification and heat recovery standpoint. Studies on source separated systems show a wide range of benefits, largely by keeping household wastewater separated, such as increased resource efficiency of nitrogen and phosphorus at the wastewater treatment plants. The contamination of heat exchanger surfaces, especially biofilm, poses a challenge when wastewater is used as a heat source and is something that has to be taken into account even when using grey water as a heat source. The result of the calculations of an individual case with preheating of domestic hot water, given a series of assumptions, resulted in operational cost savings of approximately SEK 31,000 per year and a present value of these annual savings over 20 years of approximately SEK 355,000. Energy savings amounted to approximately 63,000 kWh per year, which means a reduction of the total need for purchased energy for domestic hot water production by 67 % with an assumption of a final domestic hot water temperature of 55 °C. The sensitivity analysis shows that crucial parameters in the calculation study such as electrical and district heating price, heat pump life and discount rate entail relatively large changes in profit if allowed to vary. It is obvious that there are large amounts of energy to potentially recycle. It is also obvious that difficulties cause grey water as a source of heat not be treated easily because, among other things, the long-term development of household water use and high pollution rates are factors that must be considered in addition to the factors brought up in the sensitivity analysis. District heating and heat pump combined imply a higher investment than a single heating system, but at the same time is something that can be seen as a tool for utilizing the assumed increasing energy price variations that an increasing proportion of intermittent renewable power generation implies simply by varying heating configuration with changes in energy prices and finding the optimal share. For a property owner, it would at this point be favorable to be able to choose what the cheapest option is currently.

L'azote est connu pour influencer la sensibilité de certaines plantes à diverses maladies. Dans le cas des maladies causées par Botrytis cinerea, le rôle de la fertilisation azotée semble être variable, avec des niveaux élevés favorisant ou réduisant la gravité en fonction des études. Pour vérifier si cette variabilité pourrait être due à des différences possibles entre plantes hôtes, à la pression d'inoculum ou à un comportement différent de différentes souches de l'agent pathogène, des études ont été menées pour évaluer l'effet de différents régimes de fertilisation azotée sur la sensibilité de la tomate et de la laitue à six isolats de B. cinerea. Des effets épidémiologiques éventuels de la fertilisation azotée à travers la sporulation du pathogène et la pathogénicité de l'inoculum secondaire ont également été étudiés sur la tomate. Les plantes ont été cultivées dans un système hors-sol fertirrigué au goutte à goutte. Une nutrition azotée différentielle allant de 0,5 à 30 mM de nitrate a été appliquée pendant les quatre dernières semaines avant l'inoculation des plantes sur des feuilles (laitue) ou sur des plaies d'effeuillage (tomates). Après inoculation, les plantes ont été incubées dans des conditions propices au développement de la maladie. Sur la tomate, l'apparition de la maladie a été retardée et la sévérité globale des symptômes était plus faible pour tous les isolats aux doses de fertilisation azotée les plus élevées, indépendamment de la concentration d'inoculum. Toutefois, le taux d'expansion des lésions sur tige a été affecté différemment selon les souches, diminuant avec des niveaux croissants de fertilisation azotée pour les isolats les plus agressifs, mais augmentant pour les isolats moins agressifs. En contraste avec la tomate, la fertilisation azotée a augmenté la sévérité de la maladie sur la laitue pour tous les isolats testés. La sporulation de B. cinerea sur tomate a diminué significativement avec l'augmentation de la fertilisation azotée des plantes jusqu'à 15-30 mM de nitrate et la pathogénicité des spores a été fortement influencée par l'état nutritionnel de leur substrat de production. Elle était la plus élevée pour les spores produites sur des plantes ayant reçu des niveaux de fertilisation azotée très faibles ou très élevés (0,5 ou 30 mM nitrate) et la plus faible pour celles produites sur des plantes ayant reçu une fertilisation azotée modérée. La fertilisation des plantes a aussi fortement affectée l'efficacité de deux agents de lutte biologique (Trichoderma atroviride et Microdochium dimerum) à protéger les plaies d'effeuillage de la tomate contre B. cinerea. Les plus hauts niveaux de protection ont été obtenus avec la fertilisation azotée élevée et ceci a pu être lié à un retard dans le développement des symptômes sur les tiges, parfois associé à un ralentissement de l'expansion des lésions. Des études histologiques ont montré que la diminution de la gravité de la maladie sous fertilisation azotée élevée a été associée à une altération structurelle des cellules du mycélium de Botrytis. En présence d'un agent de lutte biologique, l'effet de l'agent pathogène a été en outre associé à une vacuolisation, dépôt de glycogène et mort des cellules mycéliennes. Les hypothèses pour expliquer ces résultats sont discutées à la lumière des effets physiologiques possibles de la fertilisation azotée sur la disponibilité des nutriments pour l'agent pathogène dans les tissus de l'hôte et de la production possible de métabolites de défense de la plante. Ces résultats ouvrent de nouvelles perspectives pour manipuler la fertilisation azotée comme un outil pour la protection intégrée des cultures maraîchères / Nitrogen (N) fertilization is known to influence the susceptibility of many plants to a variety of diseases. In the case of diseases caused by Botrytis cinerea, the role of N fertilization appears to be variable, with high levels either fostering or reducing severity depending on the studies. To test whether this variability could be due to possible differences in the host plants, inoculum pressure or in the behavior of different strains of the pathogen, studies were carried out to investigate the effect of different N fertilization regimes on the susceptibility of tomato and lettuce to six isolates of B. cinerea. Possible epidemiological effects of N fertilization through the sporulation of the pathogen and on the pathogenicity of resulting secondary inoculum were also investigated on tomato. Plants were grown in a soil-less drip-irrigation system. Differential N nutrition ranging from 0.5 to 30 mM NO3- was applied for the last four weeks prior to inoculation on the leaves (lettuce) or on leaf pruning wounds (tomato) and incubation of the plants in conditions conducive to disease development. On the tomato stems, disease onset was delayed and overall severity was lower for all isolates on plants with higher N inputs, regardless of inoculum concentration. However, the rate of stem lesion expansion was differentially affected depending on the strains, decreasing with increasing N fertilization levels for the more aggressive isolates, while increasing for the less aggressive isolates.In contrast with tomato, high N fertilization increased disease severity on lettuce for all isolates tested. On tomato plant tissue, sporulation of B. cinerea decreased significantly with increasing N fertilization up to 15-30 mM NO3- and the pathogenicity of the spores was significantly influenced by the nutritional status of their production substrate. It was highest for spores produced on plants with very low or very high N fertilization (0.5 or 30 mM NO3-) and lowest for those from plants with moderate levels of N fertilization. Plant fertilization also strongly affected the efficacy of two biocontrol agents (Trichoderma atroviride and Microdochium dimerum) to protect pruning wounds of tomato against B. cinerea. The highest levels of protection were obtained with high N fertilization and related to a delay in symptom development on the stems, sometimes associated with a slowdown in lesion expansion. Histological studies showed that the decrease in disease severity at high N fertilization was associated to structural alteration of Botrytis mycelial cells. In the presence of a biocontrol agent, the effect on the pathogen was further associated to vacuolisation, glycogen deposition and mycelial cell death. Hypotheses to explain these results are discussed in light of the possible physiological effects of nitrogen fertilization on nutrient availability for the pathogen in the host tissue and of possible production of defense metabolites by the plant. These results also open new possibilities for including the manipulation of N fertilization as a tool for the integrated protection of vegetable crops

Although early reproduction within a breeding season often leads to higher reproductive success in seasonal environments, it is still not well understood how reproductive success can be influenced by climate both indirectly through the timing of breeding or by directly altering parental behaviour. In this thesis, I investigate the role of ambient temperature in reproductive success through its effects on the timing of reproduction and brooding in a population of gray jays, Perisoreus canadensis. In chapter 2, I test whether (i) female gray jays adjust laying date in response to temperature, (ii) individual or environmental characteristics constrain this plasticity, and (iii) laying date influences reproductive success. Females laid earlier in warmer years than in colder years; females partnered with older males laid earlier than females partnered with younger males at colder temperatures, but not at warmer temperatures. Early layers were more likely to rear at least one nestling and have a dominant juvenile survive the summer. These findings suggest that male experience could advance female laying date at cold temperatures and subsequently increase the probability of a positive nesting outcome. Though cold temperatures appear to limit timing of reproduction in gray jays, previous work in this system suggests that cold temperatures could better preserve perishable winter food stores. Thus, in chapter 3, I test whether temperatures during early offspring development interact with timing of reproduction to influence reproductive performance. Colder ambient temperatures during incubation were associated with larger brood sizes than warmer temperatures among late breeders, but temperature did not influence brood size among early layers, indicating that costs of late breeding may be amplified by temperatures that are unfavourable for food storage. This thesis contributes to our understanding of the environmental factors that determine reproductive performance, both through effects on timing of reproduction and after eggs are laid.

Subject of the diploma thesis was to resolve influence of grey cast iron on penetration into cement sand. Methodology of trial was designed and its attestation was implemented in experimental and running conditions. On boundary-line cement sand and pouring metal was certified generation of complex allied substances. Created mathematical model of mechanical penetration proved influence of temperature and chemical composition of grey cast iron on range of penetration.

Developing nations face insurmountable challenges to reliably and sustainably provide energy and water to the population. These resources are intricately entwined such that decisions on the use of one affects the other (energy-water nexus). Inadequate and ageing infrastructure, increased population and connectivity, urbanization, improved standards of living and spatially uneven rainfall are some of the reasons causing this insecurity. Expanding and developing new supply infrastructure is not sustainable due to sky high costs and negative environmental impact such as increased greenhouse gas emissions and over extraction of surface water. The exponentially increasing demand, way above the capacity of supply infrastructure in most developing countries, requires urgent mitigation strategies through demand side management (DSM). The DSM strategies seek to increase efficiency of use of available resources and reducing demand from utilities in the short, medium and long term. Renewable energy, rooftop rain water harvesting, pump-storage scheme and grey water recycling are some alternatives being used to curb the insecurity. However, renewable energy and rooftop water harvesting are spasmodic in nature hampering their adoption as the sole supply options for energy and water respectively. The built environment is one of the largest energy and water consuming sectors in the world presenting a huge potential towards conserving and increasing efficiency of these resources. For this reason, coupled with the 1970s energy challenges, the concept of green buildings seeking to, among other factors, reduce the consumption of energy and water sprung up. Conventionally, policy makers, industry players and researchers have made decisions on either resource independently, with little knowledge on the effect it would have on the other. It is therefore imperative that optimal integration of alternative sources and resource efficient technologies are implemented and analysed jointly in order to achieve maximum benefits. This is a step closer to achieving green buildings while also improving energy and water security. A multifaceted approach to save energy and water should integrate appropriate resource efficient technology, alternative source and an advanced and reliable control system to coordinate their operation. In a typical South African urban residential house, water heating is one of the most energy and water intensive end uses while lawn irrigation is the highest water intensive end use occasioned by low rainfall and high evaporation. Therefore, seamless integration of these alternative supply and most resource intensive end uses provides the highest potential towards resource conservation. This thesis introduces the first practical and economical attempt to integrate various alternative energy and water supply options with efficient devices. The multifaceted approach used in this research has proven that optimal control strategy can significantly reduce the cost of these resources, bring in revenue through renewable energy sales, reuse waste water and reduce the demand for grid energy, water and waste water services. This thesis is generally divided into cold and hot water categories; both of which energy-water nexus DSM is carried out. Open-loop optimal and closed-loop model predictive (MPC) control strategies that minimize the objective while meeting present technical and operational constraints are designed. In cold water systems, open-loop optimal and MPC strategies are designed to improve water reliability through a pump storage system. Energy efficiency (EE) of the pump is achieved through optimally shifting the load to off-peak period of the time-of-use (TOU) tariff in South Africa. Thereafter, an open-loop optimal control strategy is developed for rooftop rain water harvesting for lawn irrigation. The controller ensures water is conserved by using the stored rain water and ensuring only the required amount of water is used for irrigation. Further, EE is achieved through load shifting of the pump subject to the TOU tariff. The two control strategies are then developed to operate a grey water recycling system that is useful in meeting non-potable water demand such as toilet flushing and lawn irrigation and EE is achieved through shifting of pump's load. Finally, the two control strategies are designed for an integrated rain and grey water recycling for a residential house, whose life cycle cost (LCC) analysis is carried out. The hot water category is more energy intensive, and therefore, the open-loop optimal control strategy is developed to control a heat pump water heater (HPWH) and an instantaneous shower, both powered by grid-tied renewable energy systems. Solar and wind energy are used due to their abundance in South Africa. Thereafter, the MPC strategy is developed to power same devices with renewable energy systems. In both strategies, energy is saved through the use of renewable energy sources, that also bring in revenue through sale of excess power back to the grid. In addition, water is conserved through heating the cold water in the pipes using the instantaneous shower rather than running it down the drain while waiting for hot water to arrive. LCC analysis is also carried out for this strategy. Each of the two control strategies has its strengths. The open loop optimal control is easier and cheaper to implement but is only suitable in cases where uncertainties and disturbances affecting the system do not alter the demand pattern for water in a major way. Conversely, the closed-loop MPC strategy is more complicated and costly to implement due to additional components like sensors, but comes with great robustness against uncertainties and disturbances. Both strategies are beneficial in ensuring security and reliability of energy and water is achieved. Importantly, technology alone cannot have sustainable DSM impact. Public education and awareness on importance of energy and water savings, improved efficiency and effect on supply infrastructure and greenhouse gas emissions are essential. Awareness is also important in enabling the acceptance of these technological advancements by the society. / Thesis (PhD)--University of Pretoria, 2017. / National Hub for Energy Efficiency and Demand Side Management (EEDSM) / University of Pretoria / Electrical, Electronic and Computer Engineering / PhD / Unrestricted