[ES] Desde la irrupción de los vehículos eléctricos en el mercado automotriz como una opción de transporte limpia y asequible, los fabricantes de motores han estado buscando nuevas formas de reducir la huella ambiental de los actuales motores de combustión interna alternativos (MCIA). Hoy en día, la mayoría de las investigaciones en aplicaciones de vehículos de pasajeros se centran en desarrollar aún más los motores de encendido provocado (MEP) para promover una nueva generación de sistemas de propulsión sostenibles y de alto rendimiento. En este contexto, el concepto de encendido de precámara se está convirtiendo en una solución atractiva para aumentar la eficiencia térmica de los futuros MEP para vehículos de pasajeros, debido a su capacidad de acelerar el proceso de combustión. Además, la combinación de esta estrategia de encendido con mezclas diluidas (ya sea con aire o gases de escape) tiene el potencial de mejorar aún más el rendimiento del motor. En particular, en comparación con los sistemas de precámara activa con suministro de combustible auxiliar, la versión pasiva ofrece ventajas evidentes en términos de simplicidad mecánica, ensamblaje y coste. Sin embargo, todavía existen importantes obstáculos relacionados con la comprensión de los aspectos fisicoquímicos fundamentales del concepto (turbulencia, aerodinámica, conversión de energía, dinámica de los chorros, geometría de precámara...), que en última instancia han limitado la integración de esta tecnología en producción. Por lo tanto, esta tesis doctoral pretende extender el nivel de conocimiento de este concepto de encendido mediante el uso de un modelo CFD de última generación, validado con un extenso conjunto de medidas experimentales y siguiendo una metodología especialmente desarrollada para este trabajo de investigación. Los resultados obtenidos se dividieron en tres partes: La primera parte evaluó un MEP monocilíndrico de investigación, representativo de vehículos automóviles, que integraba el concepto de precámara pasiva en condiciones estequiométricas sin dilución. Aquí se evaluó el impacto del punto de operación del motor, el avance del encendido y la geometría de la precámara sobre los procesos físicos y termoquímicos que intervienen en este concepto de combustión. La segunda parte del estudio se centró en caracterizar el concepto en condiciones diluidas con aire y recirculación de gases de escape (EGR). Se analizó en profundidad la evolución del proceso de combustión y la distribución de energía en la precámara y cámara principal para los límites de dilución experimentales. Además, también se evaluó el uso de hidrógeno para ampliar el límite de dilución con aire. La última etapa de la investigación consistió en evaluar una posible aplicación tecnológica de este concepto de encendido a partir de los conocimientos adquiridos. Por ello, se desarrolló una metodología de diseño de precámara que combina herramientas numéricas 0D/1D y CFD. Posteriormente, la metodología fue validada en el banco de ensayos del motor, y la precámara resultante ofreció buenos niveles de rendimiento térmico y fue capaz de extender el límite de dilución con EGR. Con ello, la presente tesis doctoral supone un avance significativo en el campo del análisis del impacto de la integración de sistemas avanzados en MCIA en general, y en MEP en particular, con el objetivo de mejorar sus prestaciones, emisiones o rendimiento, contribuyendo al esfuerzo que está realizando la comunidad científica para mitigar el impacto ambiental del sector del transporte. / [CAT] Des de la irrupció dels vehicles elèctrics en el mercat automotriu com una opció de transport neta i assequible, els fabricants de motors han estat buscant noves maneres de reduir la petjada ambiental dels actuals motors de combustió interna alternatius (MCIA). Hui dia, la majoria de les investigacions en aplicacions de vehicles de passatgers se centren a desenvolupar encara més els motors d'encesa provocada (MEP) per a promoure una nova generació de sistemes de propulsió sostenibles i d'alt rendiment. En aquest context, el concepte d'encesa de precàmera s'està convertint en una solució atractiva per a augmentar l'eficiència tèrmica dels futurs MEP per a vehicles de passatgers, a causa de la seua capacitat d'accelerar el procés de combustió. A més, la combinació d'aquesta estratègia d'encesa amb mescles diluïdes (siga amb aire o productes de la combustió) té el potencial de millorar encara més el rendiment del motor. En particular, en comparació amb els sistemes de precàmera activa amb subministrament de combustible auxiliar, la versió passiva ofereix avantatges evidents en termes de simplicitat mecànica, assemblatge i cost. No obstant això, encara existeixen importants obstacles relacionats amb la comprensió dels aspectes fisicoquímics fonamentals del concepte (turbulència, aerodinàmica, conversió d'energia, dinàmica d'ejecció, geometria de precàmera...), que en última instància han limitat la integració d'aquesta tecnologia a la producció en sèrie. Per tant, aquesta tesi doctoral pretén estendre el nivell de coneixement d'aquest concepte d'encesa mitjançant l'ús d'un model CFD d'última generació, validat amb un extens conjunt de mesures experimentals i seguint una metodologia especialment desenvolupada per a aquest treball de recerca. Els resultats obtinguts es divideixen en tres parts. La primera part estudia un MEP monocilíndric d'investigació, representatiu dels vehicles actuals d'automoció, que integra el concepte de precàmera passiva en condicions estequiomètriques sense dilució. Ací s'avalua l'impacte del punt d'operació del motor, l'avanç de l'encesa i la geometria de la precàmera sobre els processos físics i termoquímics que intervenen en aquest concepte de combustió. La segona part de l'estudi se centra a caracteritzar el concepte en condicions diluïdes amb aire i recirculació de gasos produïts per la combustió (EGR). S'analitza en profunditat l'evolució del procés de combustió i la distribució d'energia en la precàmera i en cambra principal per als límits de dilució experimentals. A més, també s'avalua l'ús d'hidrogen per a ampliar el límit de dilució amb aire. L'última etapa de la investigació consisteix a avaluar una possible aplicació tecnològica d'aquest concepte d'encesa a partir dels coneixements adquirits. Per això, es desenvolupa una metodologia de disseny de precàmera que combina eines numèriques 0D/1D i CFD. Posteriorment, la metodologia és validada al banc d'assajos del motor, on la precàmera resultant ofereix bons nivells de rendiment tèrmic i és capaç d'estendre el límit de dilució amb EGR. Amb això, la present tesi doctoral suposa un avanç significatiu en el camp de l'anàlisi de l'impacte de la integració de sistemes avançats en MCIA en general, i en MEP en particular, amb l'objectiu de millorar les seues prestacions, emissions o rendiment, contribuint a l'esforç que està realitzant la comunitat científica per a mitigar l'impacte ambiental del sector del transport. / [EN] Since the irruption of electric vehicles in the automotive market as a clean and affordable transportation option, engine manufacturers have been looking for new ways to reduce the environmental footprint of current internal combustion engines (ICE's). Nowadays, most of the research efforts in passenger car applications focus on further developing spark-ignition (SI) engines to promote a new generation of high-performance and sustainable powertrains. In this context, the pre-chamber ignition concept is becoming an attractive solution to increase the thermal efficiency of future light-duty SI engines, due to its inherent capability of enhancing the combustion process. Moreover, combining this ignition strategy with diluted mixtures (either with air or exhaust gases) has the potential to further improve the engine performance and reduce pollutant emissions. In particular, compared to active pre-chamber systems with an auxiliary fuel supply, the passive version provides advantages in terms of mechanical simplicity, packaging and cost-effectiveness. However, there are still major hurdles related to the understanding of the fundamental physicochemical aspects of the concept (turbulence, scavenging, energy conversion, jet dynamics, pre-chamber geometry...), that ultimately have limited the integration of this technology into production vehicles. Therefore, this doctoral thesis intends to fill these knowledge gaps by using a state-of-the-art CFD model, validated with an extensive set of engine tests and following a simulation methodology specially developed for this research work. The obtained results were divided into three parts: The first part evaluated a research single-cylinder SI engine, representative of light-duty applications, operating with the passive pre-chamber system in un-diluted stoichiome\-tric conditions. Here, the impact of the engine operating point, spark timing and pre-chamber geometry over the physical and thermochemical processes that are involved in this combustion concept were evaluated. The second part of the study focused on characterizing the concept in diluted conditions with air and exhaust gas re-circulation (EGR). The combustion evolution and energy distribution in the pre-chamber and main chamber for the experimental dilution limits were deeply analyzed. In addition, the use of hydrogen to extend the air-dilution limit was also assessed. The final part of the investigation consisted in developing a potential technological application of this ignition concept from the acquired knowledge. Therefore, a pre-chamber design methodology combining 0D/1D and CFD numerical tools was developed and validated in the engine test bench. The resulting pre-chamber offered good levels of thermal efficiency and was able to extend the EGR dilution limit. This doctoral thesis represents a significant advancement in the frame of analyzing the impact of advanced ignition systems and their integration in ICE's in general, and in SI engines in particular, with the aim of improving the global features of these powerplants (efficiency and emissions), contributing to the effort that the scientific community is carrying out to mitigate the environmental impact of the transportation sector. / Barbery Avila, II. (2023). CFD Modelling and Analysis of the Passive Pre-Chamber Ignition Concept for Future Generation Spark-Ignition Engines [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/193035

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The Constitutional Court in the Republic of South African indicated in 2006 (Laugh It Off Promotions CC v SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae), 2006 (1) SA 144 (CC)) that a senior trademark cannot be provided with anti-dilution protection if the senior trademark cannot demonstrate a probability of substantial economic harm. In the United States of America, legislation (Trademark Dilution Revision Act of 2006) corrected an earlier Supreme Court decision (Moseley v Victoria's Secret Catalogue, Inc., 537 U.S. 418 (2003)), and as a result evidence of a probability of dilution is now required to provide a senior trademark with anti-dilution protection. Senior trademarks experienced mixed success in courts in the Republic of South Africa as well as the United States of America when requesting anti-dilution protection. The reason is that when empirical evidence is offered of trademark dilution the nature of the evidence is usually limited and the method of obtaining it is often flawed. The response of brand managers to trademark infringement also seems to be limited to decisions contemplating litigation. Therefore, to assist both the legal and marketing fraternity when trademark infringement is thought to occur, this study investigates the nature and extent of trademark dilution. A literature review revealed the elements and forms (tarnishing and blurring) of trademark dilution and the motivation for using the concept ‘brand’ and the construct ‘brand equity’ to conceptualise trademark value. The limitations of previous research in measuring trademark dilution and commentary on court decisions provided the basis of the conceptualisation of trademark dilution as an undesirable effect on customer-based brand equity, operationalised as brand attitude. Brand attitude is a higher level brand value creator and five sub-components (affect, cognition, attitude valence and stability, attitude accessibility, purchase intention) were identified that measures brand attitude accurately. Brand attitude is also preceded by brand familiarity and leads to brand loyalty. Furthermore, brand attitudes can also be explained according to four types of decision-making processes: the type of decisions (high and low involvement) and type of motivations (informational and transformational). The purpose of this study was to investigate the nature and extent of trademark dilution, (tarnishing and blurring) on components of customer-based brand equity. The study used an experimental research strategy and an electronic survey instrument (Qualtrics) with self-administered questionnaires. Six hypotheses were formulated to assess whether trademark tarnishing and blurring had an effect on any component of customer-based brand equity when trademarks/brands were considered collectively and individually. The study was designed as a 3 x 2 x 2 factorial experiment. It consisted of three factors (type of dilution; type of decision; type of motivation) with different levels (undiluted/tarnish/blur; high involvement/low involvement; informational/transformational). Twelve different questionnaires were administered to a convenience sample of 3 441 potential respondents. The data generated by the 12 questionnaires was analysed using ANOVA and Mann-Whitney U tests. The results suggested that trademark tarnishing did have statistically significant effects on components of customer-brand equity as far all trademarks/brands were concerned and that the effect of trademark tarnishing and blurring were different when all trademarks/brands were considered together. Tarnishing and blurring had statistically significant effects on components of customer-based brand equity when individual trademarks/brands were considered, but the effect seemed to be specific to the type of decision (high/low involvement) taken and not the type of motivation (informational/transformational) involved. Tarnishing and blurring, when compared, had different and similar, but varying in intensity, effects on components of customer-based brand equity for individual trademarks/brands. Tarnishing and blurring, when considered separately, had different and similar, but varying in intensity, effects on components of customer-based brand equity. The study made a theoretical contribution which should be of value to members of the legal and marketing fraternity. The study showed in the first instance that trademark tarnishing and blurring are independent constructs that had different or similar, but varying in intensity, effects on components of customer-based brand equity. The effect of trademark dilution, tarnishing and blurring, is not limited to brand recall and recognition and brand attitude accessibility. Trademark tarnishing also had different or similar, but varying in strength, effects on individual trademarks/brands, as did trademark blurring. The type of decision (high or low) and type of motivation (informational or transformational) therefore play a role in the unique effect trademark tarnishing or blurring will have on components of customer-based brand equity. Secondly, the effect of trademark tarnishing and blurring may not be unfavourable by implication. In fact, blurring had a positive effect on components of customer-based brand equity, at least after a single exposure. This finding implies that trademark tarnishing has a more severe and faster effect on customer-based brand equity compared to trademark blurring. A brand manager will, as a result of the study, know how to respond, if at all, when a junior mark emerges that is similar to their senior trademark and seemingly dilutes the senior trademark. An attorney whose client requests anti-dilution protection will know, as a result of the study, whether litigation is indeed the answer to the problem. The study provides insight, not only regarding the nature of trademark dilution, as explained by the impact of trademark tarnishing and blurring on specific components of customer-based brand equity, but also regarding the extent of trademark dilution. Trademark dilution has an effect on trademarks/brands, but the effect, be it in respect of a specific component or the intensity of the effect on the component, may not be what is expected. Based on the results of this study several recommendations can be offered to brand managers and trademark attorneys. Brand managers (senior trademarks) should not respond to junior marks using their brands (senior trademarks) without first assessing the nature and extent of the effect of the junior mark on the senior trademark’s customer-based brand equity. Similarly, attorneys should also first examine the nature and extent of trademark dilution and advise their clients accordingly. Once the nature and extent of trademark dilution have been determined, a brand manager can customise his response according to the component of customer-based brand equity affected as well as the intensity of the effect. Attorneys can support at least part of their arguments to obtain anti-dilution protection for their clients, on very exact indications of the effect of use by a junior mark on customer-based brand equity. / AFRIKAANSE OPSOMMING: Die Konstitusionele Hof van die Republiek van Suid-Afrika het in 2006 (“Laugh it Off Promotions CC vs SAB International (Finance) BV t/a Sabmark International (Freedom of Expression Institute as amicus curiae),” 2006 (1) SA 144 (CC)) bevind dat ‘n senior handelsmerk nie anti-skendingsbeskerming kan geniet tensy die senior handelsmerk ‘n waarskynlikheid van wesenlike finansiële skade kan demonstreer nie. In die Verenigde State van Amerika het wetgewing ‘n Hooggeregshof-uitspraak (“Moseley v Victoria’s Secret Catalogue, Inc.,” 537 U.S. 418 (2003)) gekorrigeer sodat sederdien slegs bewys van ‘n waarskynlikheid van skending nou benodig word vir ‘n senior handelsmerk om anti-skendingsbeskerming te kan geniet. Senior handelsmerke het gemengde welslae in beide die Republiek van Suid-Afrika sowel as die Verenigde State van Amerika behaal wanneer hulle anti-skendingsbeskerming versoek het omrede die empiriese bewyse wat normaalweg aangebied is, beperkend van aard was en die data-insamelingsmetode gebrekkig. Die reaksie van handelsmerkbestuurders op handelsmerk-oortreding was tot dusver beperk tot besluite ten gunste van litigasie al dan nie. Derhalwe ondersoek hierdie studie die aard en omvang van handelsmerk-skending om sodoende beide die regskundige en bemarkingsgemeenskappe te ondersteun wanneer handelsmerk-oortreding vermoed word. ‘n Literatuur oorsig het die elemente en vorme (besmetting en verdowwing) van handelsmerk-skending geidentifiseer asook die motivering om die konsep van ‘handelsmerk’ en die konstruk van ‘handelsmerkwaarde’ te gebruik. Die beperkings van vorige navorsing om handelsmerk-skending te meet en kommentaar op hofbeslissings het die basis van die voorstelling van handelsmerk-skending as ‘n ongewenste effek op kliënt-gebaseerde handelsmerkwaarde neergelê en dit geoperasionaliseer as handelsmerk-ingesteldheid. Handelsmerk-ingesteldheid is ‘n hoë-vlak handelsmerkwaardeskepper en vyf subkomponente (gevoelsinhoud/emosie; denke/kennis; polariteit en stabiliteit van ingesteldheid; ingesteldheidstoeganklikheid/reaksie latentheid; aankoopvoorneme) is geïdentifiseer wat handelsmerk-ingesteldheid akkuraat meet. Handelsmerk-ingesteldheid word voorafgegaan deur handelsmerk-bekendheid en gevolg deur handelsmerk-lojaliteit. Verder kan handelsmerk-ingesteldheid ook verklaar word aan die hand van vier soorte besluitnemingsprosesse: die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en die tipe motivering (informatief of transformerend). Die doel van die studie was om die aard en omvang van handelsmerk-skending, (besmetting en verdowwing) op die komponente van kliënt-gebaseerde handelsmerkwaarde te ondersoek. Die studie het ‘n eksperimentele navorsingstrategie gevolg en van ‘n elektroniese opname-instrument (Qualtrics) met self-geadministreerde vraelyste gebruik gemaak. Ses hipoteses is geformuleer om vas te stel of besmetting of verdowwing ‘n effek op enige komponent van kliënt-gebaseerde handelsmerkwaarde het wanneer alle handelsmerke gesamentlik beskou word sowel as afsonderlik. Die studie was ontwerp as ‘n 3 x 2 x 2 faktoriale eksperiment. Dit het bestaan uit drie faktore (tipe skending; tipe besluit; tipe motivering) met verskillende vlakke (onbenadeel/besmet/verdof; hoë betrokkenheid/lae betrokkenheid; informatief/transformerend). Twaalf verskillende vraelyste is aan ‘n geriefsteekproef van 3 441 moontlike respondente gestuur. Die data word deur die 12 vraelyste gegenereer is met behulp van ANOVA en Mann Whitney U toetse ontleed. Die resultate het aangetoon dat besmetting ‘n statisties betekenisvolle effek op die komponente van kliënt-gebaseerde handelsmerkwaarde het wanneer die handelsmerke gesamentlik beskou word, asook dat die effek van besmetting en verdowwing verskillend is wanneer al die handelsmerke gesamentlik beskou word. Bemetting en verdowwing het statisties betekenisvolle effekte op die komponente van handelsmerkwaarde wanneer handelsmerke afsonderlik beskou word, maar die effek blyk verwant aan die tipe besluit (hoë betrokkenheid/lae betrokkenheid) te wees en nie aan die tipe motivering (informatief/transformerend) nie. Besmetting en verdowwing, wanneer dit vergelyk word, het verskillende of soortgelyke, maar veranderend invloede ten opsigte van intensiteit, effekte op die komponente van kliënt-gebaseerde handelsmerkwaarde. Die studie lewer ‘n teoretiese bydrae gelewer aan lede van die regskundige-en bemarkingsgemeenskappe. Die studie het ten eerste getoon dat handelsmerk-besmetting en –verdowwing onafhanklike konstrukte is wat verskillende of soortgelyke, maar veranderend in intensiteit, effekte op kliënt-gebaseerde handelsmerkwaarde het. Die effek van handelsmerk-skending, besmetting en verdowwing, is nie net beperk tot handelsmerk-herroeping en -herkenning en handelsmerk-ingesteldheidstoeganklikheid nie. Handelsmerk-besmetting het ook verskillende of soortgelyke, maar verskillend in intensiteit, effekte op die handelsmerke afsonderlik, wat ook geld in handelsmerk-verdowwing. Die tipe besluit (hoë betrokkenheid of lae betrokkenheid) en tipe motivering (informatief of transformerend) speel derhalwe ‘n rol in die unieke effek wat besmetting of verdowwing op die komponente van kliënt-gebaseerde handelsmerkwaarde het. Tweedens is die effek van besmetting en verdowwing nie noodwendig ongunstig nie. Trouens, verdowwing het ‘n versterkende effek op sommige komponente van kliënt-gebaseerde handelsmerkwaarde gehad, ten minste ná ‘n enkele blootstelling. Dit impliseer dat besmetting ‘n veel erger en vinniger effek op kliënt-gebaseerde handelsmerkwaarde as verdowwing het. ‘n Handelsmerkbestuurder sal na aanleiding van die studie weet hoe om te reageer, indien enigsins, wanneer ‘n junior merk verskyn wat soortgelyk aan die senior handelsmerk is. ‘n Prokureur wie se kliënt anti-skendingsbeskerming versoek sal weet, na aanleiding van die studie, of litigasie inderdaad die antwoord op die probleem is. Die studie verskaf insig, nie net ten opsigte van die aard van handelsmerkskending soos beskryf deur die impak van handelsmerkbesmetting en –verdowwing op sekere komponente van kliënt-gebaseerde handelsmerkwaarde nie, maar ook ten opsigte van die omvang van handelsmerkskending. Handelsmerkskending het ‘n effek op handelsmerke, maar die effek, of dit op ‘n sekere komponent of op die intensiteit van die effek op die kompenent mag wees, is moontlik anders as wat verwag is. Gabaseer op die resultate kan verskeie aanbevelings aan handelsmerkbestuurders en handelsmerkprokureurs gemaak word. Handelsmerkbestuurders (senior handelsmerke) behoort nie te reageer op junior merke wat hul merk (senior handelsmerk) gebruik sonder om die aard en omvang van die effek van die junior merk op die senior handelsmerk se kliënt-gebaseerde handelsmerkwaarde te bepaal nie. Eweneens behoort handelsmerkprokureurs eers die aard en omvang van die handelsmerkskending te bepaal en hul kliënte dienooreenkomstig adviseer. Sodra die aard en omvang van handelsmerkskending bepaal is, kan ‘n handelsmerkbestuurder sy reaksie volgens die geaffekteerde komponent van die handelsmerk, sowel as die intensiteit daarvan, aanpas. Prokureurs kan ten minste sommige van hul argumente om anti-skendingsbeskerming vir hul kliënte te verkry, ondersteun deur baie duidelike aanduidings van die effek van die gebruik van ‘n junior merk op kliënt-gebaseerde handelsmerkwaarde.

Ziel der Arbeit war eine Steigerung der Wasseraufnahme und Harndilution durch Supplementierung von Natriumchlorid (NaCl) oder pH-Wert-Senkung durch Zugabe von Ammoniumchlorid (NH4Cl) zur Reduktion des Harnsteinbildungspotenzials. Durch die NaCl-Zulage wurde die Harnmenge signifikant gesteigert und das spezifische Gewicht des Harns gesenkt. Eine NaCl-Gabe stellt somit einen möglichen ergänzenden therapeutischen Ansatz für eine vermehrte Ausscheidung von Kristallen dar. Eine Ansäuerung des Harns durch Zulage von NH4Cl ließ sich nicht erreichen.

Chain conformations and the presence of chain overlaps and entanglements in dilute polymer solutions have been analyzed. The fundamental problem of existence of chain overlaps in dilute solutions is related to the drag reduction phenomenon (DR). Even though DR occurs in solutions with the concentration of only few parts per million (ppm), some theories suggest that entanglements may play an important role in DR mechanism. Brownian dynamics technique have been used to perform simulations of dilute polymer solutions at rest and under shear flow. A measure of interchain contacts and two different measures of entanglements have been devised to evaluate the structure of polymer chains in solution. Simulation results have shown that overlaps and entanglements do exist in static dilute solutions as well as in solutions under shear flow. The effect of solution concentration, shear rate and molecular mass have been examined. In agreement with the solvation theory of DR mechanism, simulation results have demonstrated the importance of polymer + polymer interactions in dilute solutions.

A precisão que pode ser obtida com levantamentos com uso do Sistema de Posicionamento Global (GPS) depende de uma série de fatores, devido à grande quantidade de fontes de erros. Em geral, estas interferências podem ser modeladas e considerações são feitas de acordo com a contribuição de cada uma destas fontes de erros. Nos primórdios dos sistemas de posicionamento, o planejamento de missões era essencial para encontrar os horários em que haveria satélites suficientes para determinação da posição. Desde que o GPS foi declarado operacional, essa questão perdeu importância. Dessa forma, não há estudos conclusivos sobre a possível influência que suas posições relativas à antena do receptor causam nos resultados dos levantamentos. Esta questão foi investigada usando como ferramenta os indicadores de precisão (DOP) disponíveis. Considerações a respeito da interpretação da figura geométrica (tetraedro), cujo volume é considerado proporcional ao DOP foram estudadas. Foi verificada a confiabilidade e a contribuição da geometria nos resultados. Comparações entre valores de planejamento e levantamento foram realizadas para o posicionamento por ponto e relativo. A influência que o comprimento da linha-base tem na obtenção dos valores de indicação foi analisada assim como a influência na precisão causada por instantes de alto valor de DOP. A questão da expectativa de que horários com bons valores de DOP possam contribuir para a fixação da ambigüidade também foi esclarecida. / The obtaining precision of GPS (Global Positioning System) surveying depends on of many factors, due the several error fonts. In general, these interferences can be modeled and considerations are made as each one contributes. In the beginning of the positioning systems, the mission planning was essential to find the period of the day that would possible to have satellites enough to position determination. Since the GPS was declared operational this issue lost importance. Hence there is a lack of conclusive researches about the influence of the satellites positioning regarding the receptor antenna position may cause on the results. This issue was investigated using tools like the available precision indicators (DOP - Dilution of Precision). Considerations regarding interpretation of the geometric figure (thetraedron), that its volume is considered proportional to the DOP were analyzed. The reliability and the geometry contribution in the results were verified. Comparisons between planning and surveying values were done to the absolute and relative positioning. The influence of the baseline in indicator values determination was analyzed as the influence in the accuracy by DOP spikes. The issue regarding the expectative that the periods with good DOP values may contribute to the ambiguity fix status was also clarified.

As simulações computacionais são comumente empregadas no estudo do processo da dispersão da pluma de efluente de esgoto no mar como suporte no projeto de sistemas de emissários submarinos. Os modelos de campo próximo são uma ferramenta eficiente para prever o comportamento desses sistemas, através da previsão da diluição inicial, das principais dimensões da pluma e da concentração final de poluentes, informações úteis para o projeto do difusor. Usando modelos de campo próximo, como o NRFIELD e o UM3 do Visual Plumes, é possível simular diferentes alternativas de emissários. No entanto, a realização de muitas simulações resulta numa grande quantidade de informações que impede a obtenção de conclusões objetivas, consumindo muito tempo do projeto. Uma estratégia para um processo de simulação eficiente que permita a obtenção da máxima informação possível com um número mínimo de simulações é fundamental. Na análise dos resultados de simulações nas quais seus parâmetros de entrada são modificados de forma controlada, as causas das mudanças na resposta podem ser facilmente identificadas. Devido a isto, o uso da análise estatística foi considerado. As ferramentas estatísticas podem ser úteis na organização das simulações e na análise subsequente dos resultados. O Planejamento de Experimentos (DOE) é a metodologia estatística para uma experimentação eficiente, permitindo a identificação das variáveis estatisticamente significativas em qualquer sistema ou processo e, a Metodologia de Superfície de Resposta permite a otimização de sistemas a partir de suas variáveis estatisticamente significativas. Considerando isso, o objetivo principal desta pesquisa foi apresentar uma nova abordagem para otimizar, por meio da simulação computacional com modelos de campo próximo e da utilização das ferramentas estatísticas: Planejamento de Experimentos e Superfícies de Resposta, a quantidade de simulações necessárias para a obtenção do valor de diluição inicial mais próximo do ótimo, no projeto de emissários submarinos, através da identificação das variáveis estatisticamente significativas, na predição da diluição inicial, nos modelos de campo próximo do Visual Plumes. Os resultados do trabalho mostraram que só três variáveis geométricas, da configuração do difusor de um emissário, são estatisticamente significativas para a previsão da diluição inicial, e que apenas umas poucas simulações, estatisticamente planejadas, são indispensáveis para a obtenção de uma configuração de emissário mais eficiente. / The computational simulations are commonly employed in the study of the process of dispersion of sewage plume at sea as support in the design of submarine outfall systems. The near field models are an efficient tool to predict the behavior of these systems, by predicting the initial dilution, the main dimensions of the sewage plume and the final concentration of pollutants, useful information for the design of the diffuser. Using near field models such as NRFIELD and UM3 from Visual Plumes, it is possible to simulate different submarine outfall alternatives for their posterior comparison and analysis. However, when many simulations are conducted, it is resulted a large amount of information, which make more difficult to obtain objective conclusions and it is much more time consuming solution. A strategy for an efficient simulation process, that allows obtaining the maximum possible information with a minimum number of simulations, is quite fundamental. In the analysis of the results of simulations in which its input parameters are modified in a controlled way, the causes of the changes in the response can be easily identified. Because of this, the use of statistical analysis was considered. Statistical tools can be useful in organizing the simulations and in the subsequent analysis of the results. The Design of Experiments (DOE) is the statistical methodology to guarantee an efficient experimentation, allowing the identification of the statistically significant variables in any system or process, and the Response Surface Methodology allows the optimization of the systems using their statistically significant variables. Considering this, the main objective of this research was to present a new approach to optimize, through computational simulation with near field models and the use of statistical tools: Design of Experiments and Response Surfaces Methodology, the number of necessary simulations to obtain the initial dilution value closer to the optimum, in the design of submarine outfalls, through the identification of the statistically significant variables, in the prediction of the initial dilution, in the near field models. The results of the work showed that only three of the diffuser geometric variables are statistically significant for the initial dilution prediction, and that only a few statistically planned simulations are indispensable for obtaining a more efficient submarine outfall configuration.

A cana-de-açúcar é uma das principais culturas do sistema agrícola brasileiro, e apresenta-se atualmente em plena expansão. Porém o uso do solo e a implementação de diferentes tecnologias de manejo têm originado alterações no equilíbrio ambiental, onde importantes interações microbianas ocorrem de forma essencial para o desenvolvimento vegetal. Dentre a vasta diversidade de microrganismos do solo, destacam-se os fungos micorrízicos, organismos intimamente associados as raízes das plantas, auxiliando a mesma, dentre outras formas, na obtenção de água e nutrientes. Estes fungos, no entanto, interagem também com outros organismos do solo, como por exemplo, com a comunidade bacteriana presente neste ambiente. Desta forma, o presente trabalho buscou estudar a dinâmica de interação entre cana-de-açúcar e o fungo micorrízico arbuscular (FMA) G.clarum em solos com diferentes composições da comunidade bacteriana. A metodologia utilizada foi a \'diluição para extinção\', onde diluições seriadas (10-1; 10-3; 10-6 e 10-9) de um solo natural foram usadas para inocular o solo estéril. Sobre esta base, foi monitorada pelo período de 60 dias, a colonização da planta pelo FMA e a estruturação das comunidades bacterianas. Como resultado, foi observada uma maior colonização das raízes de cana-de-açúcar para os tratamentos inoculada com menores diluições da comunidade original (solo natural e diluições 10-1 e 10-3), sendo da mesma forma observada uma distinção entre as comunidades bacterianas destes tratamentos para os demais. Estabelecendo correlações entre os grupos microbianos e as taxas de colonização micorrízica, foi possível nomear, com base no sequenciamento massivo da região V6 do gene ribossomal 16S DNAr, a alteração conjunta da micorrização com mudanças nos grupos de Actinobacteria,Bacteriodetes,Firmicutes,Proteobacteria,Verrucomicrobiae Acidobacteria. Concluindo, este trabalho demonstra a dependência que um processo importante, como a micorrização, possui da comunidade bacteriana do solo, e indica que em áreas degradadas, com menores níveis de diversidade bacteriana, tal processo pode ocorrer com menor eficiência. / Sugarcane is an important Brazilian agricultural system crop and presents currently booming. Nevertheless, land use, and implementation of different management technologies have originated changes in environmental balance, where important microbial interactions occur as essential for plant development. Among the wide diversity of soil microorganisms, the mycorrhizal fungi is highilighted as organisms closely associated with plant roots, helping plants, in any way, to obtain water and nutrients. These fungi however, also interact with other soil organisms, such as for example, bacterial community in these environments. Thus, the present work aimed to study the dynamics of interaction between sugarcane and arbuscularmycorrhizal fungi (AMF) Glomusclarum in soils with different compositions of the bacterial community. The methodology used was \"dilution to extinction\", where serial dilutions (10-1, 10-3, 10-6 and 10-9) of a natural soil were used to inoculate a sterile soil. On this basis, were monitored along a period of 60 days, plant colonization by AMF, and structure of bacterial communities. As a result, we observed a higher colonization of roots of cane sugar for treatments inoculated with lower dilutions of the original community (natural soil and dilutions 10-1 and 10-3), and likewise observed a distinction between these bacterial communities treatments to others. Establishing correlations between microbial groups with observed rates of colonization, it was possible to name, based on the massive sequencing of the region V6 ribosomal gene 16S rDNA, the joint amendment of mycorrhiza with changes in groups of Actinobacteria; Bacteriodetes; Firmicutes, Proteobacteria; Verrucomicrobia and Acidobacteria. In conclusion, this work demonstrates the dependence of an important process, as the AMF, has tosoil bacterial community, and indicates that degraded areas, with lower levels of bacterial diversity, such a process can occur with lower efficiency.

Dentro do escopo de estudo de aspectos fundamentais e tecnológicos, este trabalho foi direcionado à avaliação do comportamento da estabilidade e da eficiência de um reator anaeróbio contendo biomassa imobilizada em espuma de poliuretano para o tratamento de água residuária sintética com concentração de aproximadamente 500 mgDQO/L. O reator, de 6 litros de volume nominal, mantido à temperatura de 30 +/- 1ºC e sob a agitação mecânica de 500 rpm, foi operado em bateladas seqüenciais com a renovação de apenas parte do volume de água residuária tratada por ciclo, ou seja, a descarga do reator não foi completa, mas apenas parcial. Neste contexto, a principal característica operacional investigada foi a relação entre o volume de água residuária afluente, o qual era alimentado a cada novo ciclo de operação, e o volume de meio contido no reator, o qual não era descarregado no ciclo anterior, mantendo-se a mesma carga orgânica volumétrica. Desta forma, foi possível verificar a flexibilidade operacional do sistema com relação ao volume de água residuária tratada a cada ciclo e o tempo de duração do ciclo para uma mesma carga orgânica. Os resultados indicaram que o reator pôde operar com diferentes relações entre o volume alimentado e o volume de meio reacional sem diminuição significativa do seu desempenho, permitindo-se, assim, maior flexibilidade operacional. Para as condições em que o volume renovado foi maior ou igual a 50% do volume de meio do reator (ciclos de 4 a 8 horas), as eficiências de remoção de matéria orgânica filtrada e não filtrada mantiveram-se no patamar de 84 e 79%, respectivamente, enquanto que nas demais condições de maior diluição inicial do afluente (ciclos de 1 e 2 horas), essas eficiências foram ligeiramente menores, em torno de 80 e 74%, respectivamente. A alta velocidade de formação de material viscoso de aparência polimérica, nas condições de maior diluição inicial do afluente, dificultou a manutenção do volume de meio reacional do reator constante. / An assessment was performed on the stability and efficiency of an anaerobic reactor containing biomass immobilized on polyurethane foam for the treatment of synthetic wastewater with organic loading of approximately 500 mgCOD/L. The reactor had a total volume of 6 L. Batch operation took place at a temperature of 30 +/- 1ºC and an agitation rate of 500 rpm. During operation only part of the treated wastewater was renewed per cycle, i.e., reactor discharge was not complete, but partial. The main operation characteristic investigated was the ratio between influent wastewater volume, which was fed at each cycle, and the volume of medium contained in the reactor, which had not been discharged in the previous cycle, maintaining the same volumetric organic load. This way, it was possible to verify operation flexibility of the system regarding treated wastewater volume in each cycle as well as cycle time duration for the same volumetric organic loading. Results indicated that the reactor was able to operate at different ratios between feed and reaction medium volume without significant loss in performance, allowing, hence, greater operation flexibility. For conditions at which renewed volume was greater than or equal to 50% of the reactor medium (cycles from 4 to 8 hours), filtered and non-filtered organic matter removal efficiencies were about 84 and 79%, respectively, whereas at conditions of higher initial influent dilution (cycles from 1 to 2 hours) these efficiencies were slightly lower, about 80 and 74%, respectively. The high formation rate of viscous polymer-like material probably of microbiological origin, at the conditions of higher initial influent dilution hindered maintenance of constant reactor medium volume.

Estudou-se a influência do fosfato na multiplicação de Saccharomyces cerevisiae em uma fermentação contínua em mini-fermentador. Determinou-se a massa seca, a concentração dos substratos, a velocidade específica de consumo dos substratos, a velocidade específica de formação de gás carbônico, velocidade específica de consumo de oxigênio e o quociente respiratório bem como, o fósforo intracelular em diversas vazões específicas de alimentação, em cultivo contínuo de levedura de panificação, em condições de substratos limitantes. Controlando-se a quantidade de fosfato no meio de alimentação de tal modo que o fosfato residual no meio de fermentação mal pudesse ser detectado, o valor da vazão específica de alimentação crítica era aparentemente aumentado de 0,23 h-1 para 0,32 h-1. Isto sugere uma possível influência do fosfato nas funções anaeróbicas e aeróbicas da levedura de panificação. / The influence of phosphate in a continuous culture was studied using mini-fermentor on the Saccharomyces cerevisiae multiplication. Dry matter, substrate concentration, specific substrate comsumption, specific carbon dioxide release, specific oxygen uptake rates and respiration quotient , as well as phosphorous content of the cells were measured in dependence on the dilutionrate. In continuous culture glicose-limited, of baker\'s yeast if the supply of phosphorous were restricted to a extent that residual phosphate in the medium could hardly be observed, the value of critical dilution rate was apparently enhanced from 0,23 h-1 to 0,32 h-1. This observation suggests a possible mediation by phosphate between anaerobic and aerobic functions of the baker\'s yeast.

A ciclagem do nitrogênio (N) apresenta dinâmica complexa, pelas múltiplas transformações e por sua mobilidade no sistema solo-planta-atmosfera. Assim, o estudo das taxas de conversão do ciclo interno de N é fundamental, visto que essas taxas têm efeito direto na produtividade e na qualidade ambiental de um agroecossistema. O objetivo deste trabalho foi avaliar o efeito da temperatura e umidade na taxa de mineralização bruta de N (TMB) em solos cultivados com canade- açúcar no estado de São Paulo, e por meio de modelo matemático, estimar a TMB considerando as variações de temperatura e umidade do solo in situ. Foram utilizados um LATOSSOLO VERMELHO distrófico (LVd) e um LATOSSOLO VERMELHO eutrófico (LVe), coletados nos municípios de Piracicaba e Santa Cruz das Palmeiras, respectivamente. As amostragens foram realizadas nas camadas de 0-10, 10-20 e 20-30 cm do solo, em julho de 2010. A quantificação da TMB em laboratório foi realizada por meio de incubações nas temperaturas de 15, 20, 25 e 30 °C, além de quatro umidades (30, 40, 60 e 80 % da capacidade máxima de retenção de água - CMRA). Foi utilizada a técnica da diluição do isótopo 15N, com aplicação de solução de (15NH4)2SO4 nas amostras de solo e determinação do teor de N-NH4 + e da abundância isotópica 48 e 96 h após a marcação. A simulação da mineralização bruta em condições de campo foi efetuada por meio das isotermas da TMB juntamente com dados de umidade e temperatura do solo dos dois ensaios. O período modelado ocorreu entre as fases de adubação e colheita da soqueira. O conteúdo de N-NH4 + do solo apresentou valores reduzidos nas diferentes temperaturas, independentemente da camada, umidade e tipo de solo. As TMB foram relativamente baixas (menores que 2,5 mg kg-1 dia-1 de N) para todos os tratamentos. Em geral, a taxa de consumo bruto (TCB) foi maior que a TMB, indicando alta imobilização/nitrificação. Foi verificado estímulo na TMB com o aumento da umidade e temperatura, para ambos os solos. A TMB e TCB foram maiores na temperatura de 25 °C e a 60 % da CMRA. A modelagem matemática indicou maior TMB entre os meses de novembro a março, marcada pelas chuvas intensas e temperaturas elevadas. O acúmulo de N-NH4 + amonificado durante os meses simulados alcançou 133 e 91 kg ha-1 para os solos LVe e LVd respectivamente.. A metodologia de diluição do isótopo 15N é uma potencial ferramenta para quantificar a mineralização de N / The N cycling has a complex dynamics, due to the multiple transformations and its mobility in the soil-plant-atmosphere. Thus, the study of the conversion rates of the N internal cycle is crucial because these rates have direct effect on yield and environmental quality of an agroecosystem. The aim of this study was to evaluate the effect of temperature and humidity on gross N mineralization (GNM) in sugarcane cropped soils in São Paulo state, and through mathematical model estimates the GNM considering the variations of soil temperature and humidity in situ. Was used a Typic Hapludox (TH) and a Typic Eutrustox (TE), sampled in the cities of Piracicaba and Santa Cruz das Palmeiras respectively. Samples were taken at 0-10, 10-20 and 20-30 cm soil, in July 2010. Quantification of GNM in the laboratory was performed by incubation at 15, 20, 25 and 30 °C, and four humidities (30, 40, 60 and 80 % of the water holding capacity - WHC). Was used the 15N isotope dilution technique, with application of (15NH4)2SO4 solution in the soil samples and subsequent determination of N-NH4 + and isotopic abundance after 48 and 96 h of labeling. The simulation of gross mineralization under field conditions was performed through the GNM isotherms and the data from soil moisture and temperature of the two sites. The modeled period was between the N fertilization and sugarcane harvesting phases. The N-NH4 + soil content showed reduced values at different temperatures, regardless of layer, moisture and soil type. The GNM were relatively low (less than 2.5 mg kg-1 day-1 of N) for all treatments. In general, the gross consumption (GC) was higher than the GNM, indicating high immobilization/nitrification. Stimulation was observed in GNM with increasing humidity and temperature, in both soils. The GNM and GC were higher at 25 °C and 60 % of WHC. Mathematical modeling indicated higher GNM between the months November to March, marked by heavy rains and high temperatures. The accumulation of mineralized N-NH4 + in the model achieved 133 and 91 kg ha-1 for soils and LVe LVd respectively. The 15N isotope dilution method is a potential tool to quantify the N mineralization.