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Avaliação da ruptura e do recrescimento de flocos na eficiência de sedimentação em água com turbidez elevada / Evaluation of the effects of breakage and regrowth of flocs on the efficiency of sedimentation in water with high turbidityPaulo Eduardo Nogueira Voltan 28 May 2007 (has links)
Durante a floculação, a agitação promove dois efeitos simultaneamente, a agregação e a ruptura. A ruptura ocorre devido à atuação de forças de cisalhamento sobre os flocos. O aumento da agitação com, conseqüentemente, aumento do gradiente de velocidade médio, em água com flocos formados, promove o aumento das forças de cisalhamento e a degradação parcial ou total dos mesmos, em poucos segundos. Retornando à condição anterior de agitação, pode ocorrer o recrescimento dos flocos. Através de ensaios em reatores estáticos (em equipamento de jarteste) foram estudados os efeitos da ruptura e da refloculação na sedimentação dos flocos, para velocidades de sedimentação entre 0,9 e 7,0 cm/min. A água de estudo foi preparada com caulinita, resultando turbidez de 100 uT, e coagulada com sulfato de alumínio. Foram realizadas as etapas de coagulação, mistura rápida, floculação, ruptura (G=75, 150 e 250 \'S POT.-1\') e refloculação (G=25, 20 e 15 \'S POT.-1\'). A ruptura, em poucos segundos, prejudicou a remoção dos flocos por sedimentação. Quanto maior o gradiente de velocidade na ruptura, maiores foram os valores da turbidez remanescente do sobrenadante, mesmo após a refloculação. A refloculação, mesmo nos primeiros minutos, diminuiu a turbidez remanescente do sobrenadante se comparada a logo após a ruptura. Quanto menor o gradiente de velocidade durante a refloculação, menores foram os valores da turbidez remanescente do sobrenadante. Apenas para velocidades de sedimentação, gradientes de velocidade de ruptura e gradientes de velocidade de refloculação menores ou iguais a 2,5 cm/min, 75 \'S POT.-1\' e 15 \'S POT.-1\', respectivamente, foi possível obter sobrenadante com valores de turbidez remanescente similares aos encontrados inicialmente, sem ruptura. / During the flocculation, the shear rate promotes two effects simultaneously, growth and breakage of flocs. The break up of flocs is caused as a result of disruptive forces. The increase of the shear rate in water with formed flocs increases the disruptive forces and it also can break the flocs partial or totally in a few seconds. Restoring the previous low shear conditions, flocs can grow back. By using the jar test equipment, the effects of breakage and reflocullation on the efficiency of floc sedimentation were studied, using settling velocities between 0.9 e 7.0 cm/min. Water of study was prepared with groundwater and kaolin, resulting a turbidity of approximately 100 NTU. Coagulation was performed by using aluminum sulfate. Coagulation, flocculation, breakage (G=75, 150 e 250 \'S POT.-1\') and reflocculation tests were carried out. In a few seconds the breakage of flocs hindered the settling removal of turbidity. The higher the average shear rate in the break-up, the higher result the residual turbidity even after the reflocculation. In the first minutes, the reflocculation decreased the residual turbidity after sedimentation if compared to the residual turbidity just after the break-up and sedimentation. The lower the average shear rate during the reflocculation, the lower result the supernatant values of residual turbidity. Supernatant could only be obtained with the value of residual turbidity similar to the values found initially (without breakage of flocs) for the settling velocity, the average velocity gradient of break-up and the average velocity gradient of reflocculation equal or less than 2.5 cm/min, 75 \'S POT.-1\' e 15 \'S POT.-1\', respectively.
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Supporting real-time mobility services with scalable flock pattern miningLACERDA, Thiago de Barros 29 July 2016 (has links)
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Previous issue date: 2016-07-29 / Pattern mining in spatio-temporal datasets is a really relevant subject in the academia and the
industry nowadays, due to its wide applicability in helping to solve real-world problems. Many
of them can be found in the context of Smart Cities, like Traffic Management, Surveillance
and Security and City Planning, to name a few. Among the various spatio-temporal patterns
that one can extract from a spatio-temporal dataset, the flock pattern is one that has gained a
lot of attention, because of its intrinsic relation with the aforementioned problems. A lot of
work has been done in the academia, in order to provide algorithms able to identify the flock
pattern. However, none of them could perform that task efficiently nor be able to scale well
when a large dataset was the analysis target. Additionally, we found that there was no system
architecture proposal that could be simple and modular enough to be used in that spatio-temporal
pattern detection problem. Given that context, this dissertation proposes a modular system
archicture designed to help solving flock pattern mining problems and possibly be reused to
other spatio-temporal mining experiments. We then use such architecture as the infrastructure
to implement an efficient flock detection algorithm, aiming at achieving considerable gains
in execution time without compromising accuracy, thus targeting real-time deployment and
on-line processing in Smart Cities. Last, but not least, we remodel our algorithm in order to take
advantage of multi-core architectures present in modern computers. Our results indicate that
our proposal outperforms the current state-of-the-art techniques, by achieving 99% CPU time
improvement. Moreover, with our multi-thread model, we were able to reduce the processing
time of our proposed algorithm by 96% in some cases. We prove the efficiency of our solution
by performing evaluation with both real and synthetic large datasets. / Detecção de padrões em dados espaço-temporais tem se mostrado um tema de muita relevância
nos dias atuais, tanto na academia quanto na indústria, devido a sua vasta aplicabilidade em
auxiliar a solucionar problemas enfrentados na sociedade. Muitos desses problemas podem
ser classificados no conexto de Cidades Inteligentes (Smart Cities), como Gerenciamento de
Tráfego, Segurança e Planejamento de Cidades. Dentre os vários padrões espaço-temporais
que podem ser extraídos de uma base de dados, o padrão de flock é um que vem atraindo
muita atenção, devido a sua relação intrínseca com os problemas mencionados anteriormente.
Muitas pesquisas vêm sendo feitas na academia, visando desenvolver algoritmos capazes de
identificar esse padrão de movimentação. Porém, nenhum deles foi capaz de executar tal tarefa
eficientemente, nem conseguiu escalar de maneira aceitável quando uma base de dados de
grande tamanho foi analisada. Além disso, não foi encontrado nos trabalhos relacionados uma
arquitetura de software que conseguisse ser simples e modular o suficiente para ser usada no
problema de detecção de padrões de flock em dados espaço-temporais. Com isso em mente, essa
dissertação propõe uma arquitetura de software modular, direcionada para solucionar problemas
de detecção desse padrão e possivelmente ser utilizada para outros experimentos envolvendo
mineração de padrões em dados espaço-temporais. Tal arquitetura foi então usada como base na
implementação de um algoritmo de detecção de flock, focando em alcançar grandes ganhos em
tempo de processamento, sem comprometer a precisão, visando então cenários de aplicações de
tempo real em Cidades Inteligentes. No fim, nós propomos uma remodelagem no nosso algoritmo
para poder utilizar ao máximo o poder de processamento oferecido pelas arquiteturas multi-core
dos processadores modernos. Nossos resultados mostraram que nossa solução conseguiu superar
propostas do estado da arte, alcançando 99% de redução no tempo de processamento total. Além
disso, nossa remodelagem multi-thread conseguiu melhorar os resultados da nossa solução em
até 96% em alguns casos. A eficiência e performance da nossa proposta foi comprovada com
avaliações feitas com bases de dados geradas sinteticamente e coletadas em experimentos reais.
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Ruptura e recrescimento de flocos em água com substâncias húmicas aquáticas coagulada com sulfato de alumínio e cloreto férrico / Breakage and regrowth of flocs in water with aquatic humic substances coagulated with aluminum sulphate and ferric chlorideLuís Truppel Constantino 30 May 2008 (has links)
Por meio de ensaios em reatores estáticos (em equipamento de jarteste) foram estudados os efeitos da ruptura e da refloculação na sedimentação dos flocos, para diferentes velocidades de sedimentação. A água de estudo foi preparada com substâncias húmicas aquáticas (SHA) extraídas de água coletada do rio Itapanhaú - Bertioga/SP, resultando cor verdadeira de 100 uH, e coagulada com sulfato de alumínio e cloreto férrico. Para os dois coagulantes, foram realizadas as etapas de coagulação, mistura rápida, floculação, ruptura (G=50, 100 e 150/s) e refloculação (G=10 e 20/s). Na sedimentação sem a ocorrência de ruptura o cloreto férrico teve um desempenho superior ao sulfato de alumínio, principalmente nas velocidades de sedimentação mais altas. Isso se deve ao fato da floculação da água coagulada com o cloreto férrico ter gerado flocos de tamanho muito superior aos flocos gerados com o sulfato de alumínio. A ruptura, em poucos segundos, prejudicou a remoção dos flocos por sedimentação. Quanto maior o gradiente de velocidade na ruptura, maiores foram os valores da cor aparente remanescente, mesmo após a refloculação. A refloculação, mesmo nos primeiros minutos, diminuiu a cor aparente remanescente se comparada a logo após a ruptura. O menor gradiente de velocidade durante a refloculação testado (10/s) apresentou menores valores da cor aparente remanescente. Tanto na água coagulada com o sulfato de alumínio quanto na coagulada com o cloreto férrico a refloculação se comportou de modo semelhante, havendo recuperação na eficiência de remoção de cor sem, porém, atingir os resultados obtidos antes da ruptura. / By using the jar test equipment, the effects of breakage and reflocullation on the efficiency of floc sedimentation were studied, using different settling velocities. Water of study was prepared with aquatic humic substances (AHS) extracted from the Itapanhaú river (Bertioga, SP, Brazil), resulting a true color of 100 uH. Coagulation was performed by using aluminum sulfate and ferric chloride. For both coagulants, coagulation, flocculation, breakage (G=50, 100 and 150/s) and reflocculation (G=10 and 20/s) tests were carried out. In the sedimentation without the floc breakage occurrence the ferric chloride had a superior performance to aluminum sulphate, mainly in higher settling velocities. This occurred because of flocculation of the ferric chloride coagulated water have generated higher size flocs than that generated with aluminum sulphate. The breakage of flocs, in few seconds, hindered the settling removal. The higher the average shear rate in the break-up, the higher result the residual turbidity even after the reflocculation. The reflocculation, even in the first minutes, decreased the apparent color if compared to the results just after the break-up and sedimentation. The lower average share rate used during the reflocculation (10/s) resulted lower values of the remaining apparent color. During the flocculation, the aluminum sulphate coagulated water as well as in the ferric chloride coagulated water held in similar way, recovering the efficiency of removal of color without, however, reach the results gotten before the breakage.
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Causes and Consequences of Hetrospecific Foraging Associations in Terrestrial Bird CommunitiesSridhar, Hari January 2013 (has links) (PDF)
The question of group-living in animals has attracted a lot of research attention. Today, we have a nuanced understanding of ultimate explanations and proximate mechanisms for group-living, as well as the genetic basis for seemingly puzzling aspects of sociality such as altruism. However, our current view of sociality has been obtained almost entirely in an intraspecific context, i.e. based on groups consisting of individuals of a single species. On the other hand, heterospecific sociality, i.e. groups formed by individuals of multiple species, has been largely ignored in group-living theory and empirical research. This is despite the fact that heterospecific sociality is widely prevalent in nature and is known to occur in many different contexts, in a variety of taxa and in both marine and terrestrial habitats.
My dissertation focuses on one of the best-known examples of heterospecific sociality, namely heterospecific foraging associations of terrestrial insectivorous birds (commonly called mixed-species flocks; flocks hereon). Flocks are found all over the world, in a variety of habitats, and include a unique suite of species in each area. Although flocks are the best-studied among different types of heterospecific associations known, most of the research has been descriptive. In other words, while we have descriptions of the richness, size and composition of flocks from many areas, we know little about why and how flocks form. Therefore, one broad objective of this dissertation was to better understand the causes of flock formation. Birds are thought to join flocks either to obtain direct foraging benefits or better protection from predators. I used different approaches to understand which of these two reasons is likely to be more important. Additionally, to situate heterospecific sociality within sociality in general, I also examined whether the mechanisms underlying flocks are similar to single-species groups or unique to a mixed-species condition. In other words, are flocks a different route to obtain the same benefits as single-species groups, or a route to obtain benefits that conspecifics cannot provide?
In the previous section, I described why understanding flocks is important from the point of view of sociality. Flocks are also important for the consequences they might have on community organization. While each flock is a collection of interacting individuals of different species, populations of species are linked in a network of interactions across multiple flocks in an area. The theoretical framework guiding our understanding of community organization is currently dominated by the idea of interspecific competition. Mutualisms or positive interactions, if any, are only expected to occur between members of different trophic levels. Only recently has the need to incorporate positive interactions between members of the same trophic level into ecological theory been emphasized. Flocks and other heterospecific associations present an important example of within-trophic level positive interactions. Therefore, the second broad objective of this dissertation was to examine the consequences of flock formation on community organization.
The objectives described above were addressed using multiple approaches in this dissertation. “Why” questions in ecology and evolution are generally tackled using manipulative experiments. Given that experiments are neither feasible nor ethical in the case of multispecies flocks in the wild, I addressed the “why” question by focusing on “who” instead. To understand “why” flocks form, I examined what kinds of species participate in flocks, who associates with whom, and who provides and who receives the benefits. This dissertation uses a combination of methods and data, including questions addressed at a global scale using descriptive information on flocks available from across the world. For other questions that were based on entirely new approaches developed in this dissertation, data were collected in a field site in the Western Ghats. In general, given the two broad objectives of this dissertation, the approaches I used were drawn from both behavioural and community ecology. The dissertation is organized in the following way:
Chapter 1: General Introduction
The first chapter provides the background to the two broad objectives of this thesis, namely understanding the causes and consequences of heterospecific foraging associations in terrestrial bird communities.
Chapter 2 (published in The American Naturalist) Based on a global dataset (55 presence-absence matrices from 24 locations in multiple continents) on the composition of flocks, I asked if flocks largely consist of ecologically similar or dissimilar species. Using null models and randomization tests followed by meta-analysis, I found that the association strength of species in flocks was strongly related to similarity in body size and foraging behaviour, and higher for congeneric compared with non-congeneric species pairs. In other words, flocks seem to consist largely of similar species. Extending group-living and social information use theory to a heterospecific context, I discuss potential behavioral mechanisms leading to positive interactions among similar species in flocks as well as ways in which competition costs are reduced. These findings highlight the need to consider positive interactions along with competition when seeking to explain community organisation.
Chapter 3 (published in Animal Behaviour) Two kinds of participants are recognized in flocks: those that join other species (‘followers’) and are therefore likely to be the recipients of the benefits of flock participation and those that are joined (‘leaders’). Through comparative analyses, using a large sample of flocks from around the world, I found (1) ‘followers’ tend to be smaller, more insectivorous, and feed in higher strata than matched species that participate in flocks to a lesser extent and (2) ‘leaders’ tend to be cooperative breeders (which are known to have well-developed anti-predatory systems) more often than matched species that are not known to lead flocks. Furthermore, meta-analyses of published results from across the world showed that bird species in terrestrial mixed-species flocks increased foraging rates and reduced vigilance compared to when they were solitary or in conspecific groups. Moreover, the increase in foraging rates was seen only in the case of flock followers and not flock leaders. These findings suggest a role for predation in the evolution of mixed-species flocking. Species that are vulnerable to predation follow species whose vigilance they can exploit. By doing so, they are able to reduce their own vigilance and forage at higher rates.
Chapter 4 (to be submitted to Behavioural Ecology and Sociobiology) In this study, conducted in a tropical evergreen forest in the Western Ghats of India, I used intraflock association patterns to generate a community-wide assessment of benefits of flock participation for different species. I assumed that individuals needed to be physically proximate to particular heterospecific individuals within flocks to obtain any direct foraging benefit (flushed prey, kleptoparasitism, copying foraging locations). Alternatively, for all anti-predation benefits, physical proximity to particular heterospecifics is not required, i.e. just being in the flock vicinity will suffice. Therefore, I used the choice of locations within flocks to infer whether individual species are obtaining direct foraging or antipredation benefits. A small subset of the bird community (5/29 species), composed of all members of the sallying guild, showed non-random physical proximity to heterospecifics within flocks. All preferred associates were from non-sallying guilds, suggesting that the sallying species were likely obtaining direct foraging benefits, either in the form of flushed or snatched prey. The majority of species (24/29) chose locations randomly with respect to heterospecifics within flocks, and thus were likely obtaining anti-predation benefits. In summary, my study indicates that direct foraging benefits are important for only a small proportion of species in flocks and therefore that predation is likely to be the main driver of flocking.
Chapter 5 (to be submitted to Oecologia) Two types of species – intraspecifically gregarious and sallying species – are thought to play important roles in flocks because studies have shown they attract other flock participants. However, it is not clear why these types of species are attractive, i.e. are they cues for flocks or do they directly provide benefits to other species? It is also not known whether these types are essential for flock formation. In this study, in a tropical evergreen forest in the Western Ghats of India, I used a novel approach to address these questions. Flocks contain anywhere between two and tens of species. My approach focused on the simplest, i.e. two-species, flocks. In two-species flocks, attraction between species must be based on direct benefit to at least one of the species. Therefore, only species combinations that result in benefit to at least one species will occur as two species flocks. Further, by examining leading and following behaviour in these combinations, I could also determine the direction of benefit-flow. Finally, given that all flocks pass through a two-species step, examining which two-species combinations are joined by other species helped understand species roles in flock formation. I found that intraspecifically gregarious species, but not sallying species, were disproportionately represented in two-species flocks, always provided the benefits when present, and that flocks containing them were joined significantly more often. Therefore, intraspecifically gregarious species, but not sallying species, play a role in providing flock benefits and flock formation. Moreover, given that most (7/8) intraspecifically gregarious species in my study site played these roles, the intraspecifically gregarious species guild can be considered an example of a within-trophic level “keystone”.
Chapter 6 (“in press” in Oikos) There is a growing recognition of the need to integrate non-trophic interactions into ecological networks for a better understanding of whole-community organization. To achieve this, the first step is to build networks of individual non-trophic interactions. In this study, I analyzed the network of interdependencies among bird species that participated in flocks in an evergreen forest site in the Western Ghats, India. I found that flock networks contain a small core of highly important species that other species are strongly dependent on, a pattern seen in many other biological networks. Further, I found that structural importance of species in the network was strongly correlated to functional importance of species at the individual flock level. Finally, comparisons with flock networks from other Asian forests showed that the same taxonomic groups were important in general, suggesting that species importance was an intrinsic trait and not dependent on local ecological conditions. Hence, given a list of species in an area, it may be possible to predict which ones are likely to be important.
Chapter 7: Conclusions
In this section, I provide a summary of the main findings of this dissertation, discuss the main conclusions with regard to each of the two broad objectives and finally suggest future lines of investigation to further understand the causes and consequences of flock formation and heterospecific sociality in general.
In summary, the work presented in this dissertation provides a picture of how and why flocks form and their likely consequences for community organization. The main driver of flock formation seems to be protection from predators, although a few species do obtain direct foraging benefits. Additionally, given that I found flocks to largely be groupings of similar species, the mechanisms through which benefits are obtained are likely to be similar to those in single-species groups. In other words, flocks are possibly a way for species that are unable to group with conspecifics, to obtain group-living benefits. My finding, that flocks largely consisted of similar species, also questions the stereotyping of interactions between similar species in communities as competitive. Other results from this study demonstrate the importance of intraspecifically gregarious species in flocks. Such species are the main providers of benefits to other flock participants and seem essential for flock formation. Finally, network analysis showed that a small core of species, mainly including species known to provide benefits at the individual flock level, are disproportionately important in the emergent community-level network of interdependencies. Such species are possibly one of the first examples of within-trophic level “keystones” discovered. Apart from the findings, this study also provides a set of new approaches and analytical frameworks that can be used to examine other multispecies foraging groups and heterospecific foraging associations in other contexts.
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The evaluation of a South African fine wool genetic resource flockOlivier, Willem J. 04 1900 (has links)
Thesis (PhD(Agric))--Stellenbosch University, 2014. / ENGLISH ABSTRACT: This study set out to determine (co)variance components for the important production, reproduction and
conformation traits of a South African fine wool resource flock that was established at the request of the
South African wool industry. A secondary aim was to assess progeny of these animals under pastoral
conditions in areas where the production of fine wool is uncommon. The Cradock fine wool Merino stud
was established in 1988 with ewes bought from producers with the finest clips in South Africa. Data
collected from 1988 to 2010 were used to estimate the (co)variances for the genetic fine wool resource
flock. The quantification of the interdependencies of fibre diameter (FD) with production, reproduction and
subjective traits were the main objective of this study. It is evident from the results of this study that FD is
a highly heritable (0.63 ± 0.03) trait, which can lead to marked genetic progress provided that there are
adequate levels of phenotypic variation available during selection. Fibre diameter was unfavourably
correlated with body weight (0.30 ± 0.05), clean fleece weight (0.24 ± 0.05) and reproduction (0.59 ±
0.18), which implies that selection for reduced FD can have a detrimental effect on all these traits.
Despite these unfavourable genetic correlations genetic gain in the other economical important traits was
achievable in the stud (-0.129 ± 0.033). These results were supported by the results obtained during the
evaluation of progeny of this stud under pastoral conditions where the production and reproduction of the
fine wool animals were comparable with medium wool animals. It can therefore be concluded that
selection for reduced FD can be practiced without detrimental effects on the economically important traits
and subsequently the profitability of the sheep enterprise, as long as breeders have a reasonable
selection objective based on economic considerations. / AFRIKAANSE OPSOMMING: Hierdie studie het dit ten doel gehad om (ko)variansie komponente vir die belangrike produksie,
reproduksie en subjektiewe eienskappe in 'n Suid-Afrikaanse fyn wol hulpbronkudde, wat gevestig is op
versoek van die Suid-Afrikaanse wolbedryf te bepaal. 'n Sekondêre doel was om die nageslag van
hierdie diere onder veldtoestande te evalueer in gebiede waar die produksie van fynwol ongewoon is. Die
Cradock fynwol Merino stoet is in 1988 gestig met die aankoop van ooie van produsente met die fynste
skeersels in Suid-Afrika. Data wat ingesamel is vanaf 1988 tot 2010 is gebruik in die bepaling van
(ko)variansie komponente vir hierdie genetiese fynwolkudde. Die kwatifisering van die interafhanklikheid
van veseldikte (VD) met produksie, reproduksie en subjektiewe eienskappe was die hoofdoel van die
studie. Dit is duidelik uit die resultate van die studie dat VD `n hoogs oorerflike (0.63 ± 0.03) eienskap is,
wat tot vinnige vordering in VD kan lei indien genoegsame fenotipiese variasie beskikbaar is tydens
seleksie. Veseldikte is ongunstig gekorreleer met liggaamsgewig (0.30 ± 0.05), skoonvaggewig (0.24 ±
0.05) en reproduksie (0.59 ± 0.18), wat beteken dat seleksie vir ʼn verlaagde VD nadelige vordering in
hierdie eienskappe tot gevolg kan hê. Ten spyte van hierdie ongunstige genetiese korrelasies was die
genetiese vordering in die ekonomies belangrike eienskappe haalbaar in die kudde wat ondersoek is (-
0.129 ± 0.033). Die laasgenoemde resultate word ondersteun deur die bevindinge dat die nageslag van
hierdie stoet se produksie en reproduksie ooreengestem het met medium wol diere onder veldtoestande.
Die gevolgtrekking wat gemaak kan word uit die studie is dat VD verlaag kan word sonder nadelige
gevolge in die ekonomies belangrike eienskappe, asook die van `n skaapboerdery onderneming. Om dit
te vermag moet telers `n aanvaarbare benadering tot seleksie, gegrond op ekonomiese beginsels, volg.
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Carbon K-Shell X-Ray and Auger-Electron Cross Sections and Fluorescence Yields for Selected Molecular Gases by 0.6 To 2 .0 MeV Proton ImpactBhalla, Raj P. (Raj Pal), 1948 08 1900 (has links)
Absolute K-shell x-ray cross sections and Auger-electron cross sections are measured for carbon for 0.6 to 2.0 MeV proton incident on CH₄, n-C₄H₁₀ (n-Butane), i-C₄H₁₀ (isobutane), C₆H₆ (Benzene), C₂H₂ (Acetylene), CO and CO₂. Carbon K-shell fluorescence yields are calculated from the measurements of x-ray and Auger-electron cross sections. X-ray cross sections are measured using a variable geometry end window proportional counter. An alternate method is described for the measurement of the transmission of the proportional counter window. Auger electrons are detected by using a constant transmission energy Π/4 parallel pi ate electrostatic analyzer. Absolute carbon K-shell x-ray cross sections for CH₄ are compared to the known results of Khan et al. (1965). Auger-electron cross sections for proton impact on CH₄ are compared to the known experimental values of RΦdbro et al. (1979), and to the theoretical predictions of the first Born and ECPSSR. The data is in good agreement with both the first Born and ECPSSR, and within our experimental uncertainties with the measurements of RΦdbro et al. The x-ray cross sections, Auger-electron cross sections and fluorescence yields are plotted as a function of the Pauling charge, and show significant variations. These changes in the x-ray cross sections are compared to a model based on the number of electrons present in the 2s and 2p sub shells of these carbon based molecules. The changes in the Auger-electron cross sections are compared to the calculations of Matthews and Hopkins. The variation in the fluorescence yield is explained on the basis of the multiconfiguration Dirac-Fock model.
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"En inställd spelning är en spelning det också..." : Ulf Lundells olika realiteter och identiteter i romanerna Jack, En varg söker sin flock och VärmenHermansson, Johnny January 2009 (has links)
Ulf Lundell is one of the most famous songwriters and authors in Sweden. He has written fifteen works of fiction and they’ve all same theme – a lonely man trying to look into his own past life. They are all built on a character, writing from an I-perspective, having a bit of Lundells own biography in there’s personality. The aim of his thesis is to find out how Ulf Lundell presents him self in his fictive characters, and will trace the authors development from a psychological point of view. The theoretic starting points are Lacans Freudian concepts “idealego”, “egoideal” and “the superego”, describing the psychological alteration at the author. The examination contains an analysis of Lundells novels Jack, En varg söker sin flock and Värmen, and throws light on the relationship between the author and his characters, and how it developes and changes with Lundells literary development. In this consideration are narrative theories a basic factor. This work will also try to illustrate what has inspired Lundell in creating his fiction figures, and finally how he creates his own lived life on these literary characters.
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Entwicklung neuartiger Scaffolds für das Tissue Engineering mittels FlocktechnologieWalther, Anja 04 October 2010 (has links) (PDF)
Flocktechnologie ist eine im Bereich der Textiltechnik angewandte Methode, bei der kurze Fasern nahezu senkrecht auf ein vorher mit Klebstoff beschichtetes Substrat aufgebracht werden.
In der vorliegenden Arbeit wurde die elektrostatische Beflockung als Methode zur Herstellung von porösen, dreidimensionalen Scaffolds für das Tissue Engineering von Knorpel und Knochen etabliert. Dieser neuartige Scaffoldtyp wurde eingehend charakterisiert und in Zellversuchen im Hinblick auf seine Biokompatibilität untersucht. Dabei zeigte sich, dass verschiedene Zellen im Scaffold proliferieren und differenzieren können. Die in der Arbeit beschriebenen Flockscaffolds stellen somit eine vielversprechende Matrix für die Therapie von Gelenkknorpeldefekten dar.
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Využití gest v uživatelských rozhraních / Gestures in User InterfacesBednář, Luboš January 2012 (has links)
This master thesis deals with the use of gestures in user interfaces. The goal of this thesis is to create library for hand tracking and gesture recognition in real time. For hand tracking was choosen algorithm Flock of Features. Classification of gestures is done by using algorithm DTW. This thesis also contains stage design, design and implementation of a system that uses this library. Within the tests was tested control of various application using this library.
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Topologica linteractions in a multi-layered flocking system / Topologiska interaktioner i ett flerskiktigt flockningssystemLiedholm, Malin January 2023 (has links)
With the multi-layered flocking system it is possible to simulate flocks that contain different types of agents that can be of various different sizes (variations in bounding radius and height). In the original implementation, the multi-layered flocking system uses a metric distance to find the nearest-neighbours of agents. However, results from real life field studies suggest that animals interact with each other in a flock using a topological distance. The goal of this thesis is therefore to implement a version of the multi-layered flocking system that uses a topological distance for interaction between agents. This is done by adapting two methods that are used to find the k-nearest neighbours (kNN), namely the original spatial partitioning method (OSP method) and the enhanced spatial partitioning method (ESP method), to work with the multi-layered flocking system. The aim is to compare the performance of these methods in terms of query time for four different flocking scenarios (standard, obstacle, follow and steer away). The implementation contains two types of agents of two different sizes. In the standard scenario all agents move together as a flock. The obstacle scenario is similar to the standard scenario with the addition that the simulation space contains stationary obstacles. In the follow scenario the smaller sized agents follow the bigger sized agents, and in the steer away scenario the smaller sized agents steer away from the bigger sized agents. An evaluation of how different numbers of kNN affect the collective motion (polarization, extension and frequency of collisions) of the flock in the four different scenarios is also done. The evaluation was performed by implementing the multi-layered flocking system in the Unity game engine, and running simulations with flocks of different sizes (125-3125 agents) and using different numbers of interacting kNN (k=5,10,15,20) for each of the scenarios. The results show that the ESP method on average is at least twice as fast compared to the OSP method in all four flocking scenarios, and the improvement in performance in query time did not differ much between the scenarios. Moreover, a value of k=10 was shown to be a good compromise between having fast kNN query times for the ESP method, but still having flocks of agents moving in a collective manner. / Med ett flerskiktigt flockningssystem är det möjligt att simulera flockar som innehåller olika typer av agenter som kan vara av olika storlekar (variation i begränsningsradie och längd). I den ursprungliga implementeringen av det flerskiktigt flockningssystem används ett metriskt avstånd för att hitta de närmaste grannarna till agenterna. Resultat från fältstudier tyder dock på att i verkligheten interagerar djur i en flock med varandra genom ett topologiskt avstånd. Målet med denna avhandling är därför att implementera en version av det flerskiktigt flockningssystem som använder ett topologiskt avstånd för att hitta de närmaste grannarna till agenterna. Detta görs genom att anpassa två metoder som kan användas för att hitta en agents k-närmaste grannar till det flerskiktigt flockningssystem. Dessa två metoder kallas den ursprungliga spatiala partitioneringsmetoden (OSP metoden) och den förbättrade spatiala partitioneringsmetoden (ESP metoden). Syftet är att jämföra prestandan mellan dessa två metoder, vilket mäts i tid som det tar att hitta de k-närmaste grannarna för varje metod. Jämförelser genomförs för fyra olika typer av scenarion (standard, hinder, följ och styr ifrån). I standard scenariot rör sig alla agenter tillsammans som en flock. Hinder scenariot liknar standard scenariot med tillägget att simuleringsmiljön består av ett antal stationära hinder. I följ scenariot så följer de mindre agenterna de större agenterna, och i styr ifrån scenariot så försöker de mindre agenterna fly från de större agenterna. Vidare görs en utvärdering av hur olika antal k-närmaste grannar påverkar den totala flockens samlade rörelse (polarisering, förlängning och frekvens av kollisioner) för de olika scenarierna. Utvärderingen görs genom att implementera det flerskiktiga flockningssystemet med de ovan nämnda k-närmaste grannar metoderna i spelmotorn Unity. Ett flertal simuleringar genomförs sedan för de fyra scenarierna och dessa består av olika flockstorlekar (125-3125 agenter) och använder olika värden på k (k=5,10,15,20). Resultaten visar att ESP metoden i genomsnitt är dubbelt så snabb jämfört med OSP metoden. Dessutom visades ett värde på k=10 vara en bra kompromiss mellan att snabbt hitta de k-närmaste grannarna när ESP metoden används, men också ha flockar av agenter som rör sig kollektivt.
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