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1

Reed, Brian, and n/a. "A survey of regular teachers' concerns towards the integration of disabled children in state primary schools, Bendigo region, Victoria." University of Canberra. Education, 1990. http://erl.canberra.edu.au./public/adt-AUC20061107.100059.

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The integration of disabled children into regular schools is a current educational and social issue causing widespread interest, concern and debate throughout Australia. The most controversial and innovative adoption of integration policy has occurred in Victoria since the release of the Collins Report in 1984. The present study was conducted in 26 State primary schools in the Bendigo area of the Loddon Campaspe Mallee region of Victoria where disabled children had been integrated in regular classrooms with the assistance of a paid teacher aide during 1988. The purpose of the study was to survey the concerns of those teachers into whose classes children with disabilities had been integrated. The Stages of Concern (SoC) dimension of the Concerns-Based Adoption Model (C-BAM) was chosen as the research methodology. C-BAM was developed at the Research and Development Center for Teacher Education, University of Texas at Austin, and for the purpose of this study, the methodology consisted of a questionnaire of 35 standardized items (the Stages of Concern Questionnaire), and a School Survey. The study set out to identify the concerns of teachers (ii) toward integration, and to establish reasons why teachers are at particular stages of concern. Factors included teachers' age, gender, number of years of teaching experience, qualifications and in-service training. Other issues related to the disabled children themselves, the school, and factors such as availability of resources, funding levels, and access to support systems. This study developed from the policy document Integration in Victorian Education (the Collins Report, 1984). Since then, the Ministry of Education has published two additional booklets (in January and February, 1987), which partly address some of the issues included in this thesis. These include resourcing, in-servicing and the legal implications of the innovation. The analysis of the data points to major shortcomings which will jeopardize the implementation process and the likely success of the innovation. A number of recommendations have been suggested, with particular reference to the pre-service and in-service training of teachers, and issues relating to funding and resources. The findings have implications for all classroom teachers, as potentially all are required to accept disabled children into their classes. The results and recommendations also have relevance for the Ministry of Education, whose responsibility it is to ensure that the integration of disabled children into regular classes is fully supported at a government level, and for training institutions, whose task it is to provide appropriate pre-service and in-service programs for present and future classroom teachers.
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Schneider, Carri Anne. "When journalism and scholarship collide a critical analysis of Newsweek's annual report on America's top high schools /." Cincinnati, Ohio University of Cincinnati, 2007. http://www.ohiolink.edu/etd/view.cgi?ucin1178554216.

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Thesis (Dr. of Education)--University of Cincinnati, 2007.
Title from electronic thesis title page (viewed July 19, 2007). Includes abstract. Keywords: achievement gap; media; critical theory; critical pedagogy; critical race theory; systemic racism; rank; high school; Advanced Placement; Newsweek; social justice Includes bibliographical references.
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3

Schneider, Carri Anne. "When Journalism and Scholarship Collide: A Critical Analysis of Newsweek’s Annual Report on America’s Top High Schools." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1178554216.

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Quinteros, Espino Norah Miryam. "Estudio comparativo de la actividad antibacteriana y antioxidante de los extractos etanólicos de Croton thurifer Kunth y Croton collinus Kunth." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/7452.

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Evalúa de forma comparativa la actividad antibacteriana y antioxidante de los extractos etanólicos de las hojas de Croton thurifer Kunth y Croton collinus Kunth. Se realiza un screening fitoquímico preliminar de los extractos etanólicos de las hojas de Croton thurifer Kunth y Croton collinus Kunth, detectándose la presencia de flavonoides, alcaloides, saponinas y esteroides para ambas especies. La actividad antibacteriana se determina utilizando el método de microdilución colorimétrica en microplacas frente a las cepas Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 8739, Bacillus subtilis ATCC 6633 y Pseudomonas aeruginosa ATCC 27853; los resultados se evalúan mediante la determinación de la concentración mínima inhibitoria de los extractos contra las bacterias en estudio. El extracto etanólico de las hojas de Croton thurifer Kunth presenta actividad antibacteriana frente a Bacillus subtilis ATCC 6633 con una CMI = 1000 μg/mL. La actividad antioxidante se evalúa mediante el método del radical libre 1,1-difenil-2-picril-hidrazilo (DPPH); los resultados se expresan por medio del valor de la IC50. El extracto etanólico de las hojas de Croton thurifer Kunth presenta una mayor IC50, con un valor de 28,4 μg/mL, en comparación con el extracto etanólico de las hojas de Croton collinus Kunth, que mostró un IC50 de 62,42 μg/mL.
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Cucho, Medrano Juana Liz Leslie, and Beingolea Sammy Wesley Mendoza. "Determinación de la composición química mediante cromatografía de gases/ espectrometría de masas (CG/EM), actividad antimicrobiana y antioxidante de los aceites esenciales de las especies Croton adipatus, Croton thurifer y Croton collinus." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/7735.

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Evalúa la composición química, actividad antimicrobiana y antioxidante de los aceites esenciales de Croton adipatus Kunth, Croton thurifer Kunth y Croton collinus Kunth. Los aceites esenciales fueron extraídos de las hojas de las especies seleccionadas por hidrodestilación y las composiciones químicas fueron determinadas por Cromatografía de gases acoplada a espectrometría de masas (CG/EM). Las actividades antimicrobianas fueron evaluadas usando el método de difusión en agar y microdilución colorimétrica contra Staphylococcus aureus ATCC 25923, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 9027 y Candida albicans ATCC 10231. La actividad antioxidante se determinó mediante el método de captación de radical libre (DPPH). El aceite esencial de Croton adipatus Kunth mostró un mayor número de componentes (46), seguido por Croton collinus Kunth (38) y Croton thurifer Kunth (35). Los principales componentes encontrados para Croton adipatus Kunth fueron ȕ-mirceno (18,γ4%), α-thuyeno (12,69%), D-limoneno (10,94%), α-felandreno (8,19%) y ȕ-elemeno (6,47%). Mientras que para el aceite esencial de Croton collinus Kunth fueron ȕ-cariofileno (44,7%), D-limoneno (8,73%), ȕ-thuyeno (6,96%), ȕ-mirceno (6,79%) y ȕ-elemeno (6,7%). Y para Croton thurifer Kunth fueron los componentes desconocidos (C10H16: 22,38%), (C15H26O: 21,8%), ȕ-elemeno (11,87%) y germacreno D (10,22%). El aceite esencial de Croton adipatus Kunth presentó actividad antimicrobiana moderada frente a Bacillus subtilis ATCC 6633 (0,31 µL/mL) y actividad débil frente a Candida albicans ATCC 10231 (0,63 µL/mL); para Croton thurifer Kunth actividad moderada frente a Staphylococcus aureus ATCC 25923 (0,31 µL/mL) y Bacillus subtilis ATCC 6633 (0,16 µL/mL); y finalmente para Croton collinus Kunth buena actividad frente a Bacillus subtilis ATCC 6633 (0,08 µL/mL) y actividad débil frente a Candida albicans ATCC 10231 (1,25 µL/mL). Los aceites esenciales de Croton adipatus Kunth, Croton thurifer Kunth y Croton collinus Kunth no presentaron actividad antioxidante para el método DPPH.
Universidad Nacional Mayor de San Marcos (Lima). Vicerrectorado de Investigación y Posgrado
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6

Keller-Schmidt, Stephanie. "Stochastic Tree Models for Macroevolution." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-96504.

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Phylogenetic trees capture the relationships between species and can be investigated by morphological and/or molecular data. When focusing on macroevolution, one considers the large-scale history of life with evolutionary changes affecting a single species of the entire clade leading to the enormous diversity of species obtained today. One major problem of biology is the explanation of this biodiversity. Therefore, one may ask which kind of macroevolutionary processes have given rise to observable tree shapes or patterns of species distribution which refers to the appearance of branching orders and time periods. Thus, with an increasing number of known species in the context of phylogenetic studies, testing hypotheses about evolution by analyzing the tree shape of the resulting phylogenetic trees became matter of particular interest. The attention of using those reconstructed phylogenies for studying evolutionary processes increased during the last decades. Many paleontologists (Raup et al., 1973; Gould et al., 1977; Gilinsky and Good, 1989; Nee, 2004) tried to describe such patterns of macroevolution by using models for growing trees. Those models describe stochastic processes to generate phylogenetic trees. Yule (1925) was the first who introduced such a model, the Equal Rate Markov (ERM) model, in the context of biological branching based on a continuous-time, uneven branching process. In the last decades, further dynamical models were proposed (Yule, 1925; Aldous, 1996; Nee, 2006; Rosen, 1978; Ford, 2005; Hernández-García et al., 2010) to address the investigation of tree shapes and hence, capture the rules of macroevolutionary forces. A common model, is the Aldous\\\' Branching (AB) model, which is known for generating trees with a similar structure of \\\"real\\\" trees. To infer those macroevolutionary forces structures, estimated trees are analyzed and compared to simulated trees generated by models. There are a few drawbacks on recent models such as a missing biological motivation or the generated tree shape does not fit well to one observed in empirical trees. The central aim of this thesis is the development and study of new biologically motivated approaches which might help to better understand or even discover biological forces which lead to the huge diversity of organisms. The first approach, called age model, can be defined as a stochastic procedure which describes the growth of binary trees by an iterative stochastic attachment of leaves, similar to the ERM model. At difference with the latter, the branching rate at each clade is no longer constant, but decreasing in time, i.e., with the age. Thus, species involved in recent speciation events have a tendency to speciate again. The second introduced model, is a branching process which mimics the evolution of species driven by innovations. The process involves a separation of time scales. Rare innovation events trigger rapid cascades of diversification where a feature combines with previously existing features. The model is called innovation model. Three data sets of estimated phylogenetic trees are used to analyze and compare the produced tree shape of the new growth models. A tree shape statistic considering a variety of imbalance measurements is performed. Results show that simulated trees of both growth models fit well to the tree shape observed in real trees. In a further study, a likelihood analysis is performed in order to rank models with respect to their ability to explain observed tree shapes. Results show that the likelihoods of the age model and the AB model are clearly correlated under the trees in the databases when considering small and medium-sized trees with up to 19 leaves. For a data set, representing of phylogenetic trees of protein families, the age model outperforms the AB model. But for another data set, representing phylogenetic trees of species, the AB model performs slightly better. To support this observation a further analysis using larger trees is necessary. But an exact computation of likelihoods for large trees implies a huge computational effort. Therefore, an efficient method for likelihood estimation is proposed and compared to the estimation using a naive sampling strategy. Nevertheless, both models describe the tree generation process in a way which is easy to interpret biologically. Another interesting field of research in biology is the coevolution between species. This is the interaction of species across groups such that the evolution of a species from one group can be triggered by a species from another group. Most prominent examples are systems of host species and their associated parasites. One problem is the reconciliation of the common history of both groups of species and to predict the associations between ancestral hosts and their parasites. To solve this problem some algorithmic methods have been developed in recent years. But only a few host parasite systems have been analyzed in sufficient detail which makes an evaluation of these methods complex. Within the scope of coevolution, the proposed age model is applied to the generation of cophylogenies to evaluate such host parasite reconciliation methods. The presented age model as well as the innovation model produce tree shapes which are similar to obtained tree structures of estimated trees. Both models describe an evolutionary dynamics and might provide a further opportunity to infer macroevolutionary processes which lead to the biodiversity which can be obtained today. Furthermore with the application of the age model in the context of coevolution by generating a useful benchmark set of cophylogenies is a first step towards systematic studies on evaluating reconciliation methods.
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Bendezú, Ccanto Jessica Yvonne. "Efecto de la germinación de tres variedades de quinua: Roja (INIA-415 Pasankalla), Negra (INIA 420-Negra Collana) y Blanca (Salcedo INIA) en la formulación y elaboración de una bebida funcional con capacidad antioxidante." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2018. https://hdl.handle.net/20.500.12672/10085.

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La quinua es un grano con alto valor proteico, vitaminas y aminoácidos, recientemente popularizado en mercados internacionales sobre todo por sus propiedades, beneficios y usos en la cocina; el presente estudio tuvo como objetivo evaluar el efecto de la germinación en la capacidad antioxidante de tres variedades de quinua: Blanca (Salcedo INIA), roja (INIA-415 Pasankalla) y negra (INIA 420-Negra Collana) en la formulación y elaboración de una bebida. Se utilizó un diseño de mezcla obteniendo 10 tratamientos con niveles codificados de 0-3 para las variables independientes (quinua blanca germinada, quinua roja germinada y quinua negra germinada). El modelo propuesto constó de 3 componentes y 10 tratamientos que tuvieron como factor respuesta a la capacidad antioxidante y la aceptabilidad de los consumidores. Los 10 tratamientos fueron sometidos a una prueba de aceptabilidad sensorial a 60 panelistas no entrenados usando el diseño de bloques incompletos. Se midió la capacidad antioxidante a cada tratamiento usando el método ABTS obteniendo 15.91 y 21.60 uM ET/ml para el tratamiento con menor y mayor capacidad antioxidante respectivamente. Los 10 tratamientos fueron comparados con 10 tratamientos realizados con quinua sin germinar en las mismas condiciones; los resultados finales de aceptabilidad y capacidad antioxidante fueron ingresados al programa de diseño de mezcla obteniendo como tratamiento óptimo a la formulación cuya composición consistió de 81,67% de quinua negra germinada y 18,33% de quinua blanca germinada; adicionalmente se realizó el análisis proximal del tratamiento optimizado obteniendo una bebida de quinua germinada con 67.44 calorías por una porción de 200g y con 1.93% de proteínas por cada 100g de bebida. La bebida de quinua elaborada a partir de tres variedades de quinua germinada representa una alternativa novedosa a los actuales productos bebibles que se comercializan en el Perú, por su contenido en antioxidantes y la fácil preparación.
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Steinbach, Gabi, Dennis Nissen, Manfred Albrecht, Ekaterina V. Novak, Pedro A. Sánchez, Sofia S. Kantorovich, Sibylle Gemming, and Artur Erbe. "Bistable self-assembly in homogeneous colloidal systems for flexible modular architectures." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-202517.

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This paper presents a homogeneous system of magnetic colloidal particles that self-assembles via two structural patterns of different symmetry. Based on a qualitative comparison between a real magnetic particles system, analytical calculations and molecular dynamics simulations, it is shown that bistability can be achieved by a proper tailoring of an anisotropic magnetization distribution inside the particles. The presented bistability opens new possibilities to form two-dimensionally extended and flexible structures where the connectivity between the particles can be changed in vivo
Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Bulaitis, Zoe Hope. "Articulations of value in the humanities : the contemporary neoliberal university and our Victorian inheritance." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/33626.

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This thesis traces the shift from liberal to neoliberal education from the nineteenth century to the present day, in order to provide a rich and previously underdeveloped narrative of value in higher education in England. Rather than attempting to justify the value of the humanities within the presiding economic frameworks, or writing a defence against market rationalism, this thesis offers an original contribution through an immersion in historical, financial, and critical debates concerning educational policy. Drawing upon close reading and discursive analysis, this thesis constructs a nuanced map of the intersections of value in the humanities. The discussion encompasses an exploration of policymaking practices, scientific discourse, mediated representations, and public cultural life. The structure of the thesis is as follows. The introductory chapter outlines the overarching methodology by defining the contemporary period of this project (2008-14), establishing relevant scholarship, and drawing out the correspondences between the nineteenth century and the present day. Chapter one establishes a history of the Payment by Results approach in policymaking, first established in the Revised Code of Education (1862) and recently re-introduced in the reforms of the Browne Report (2010). Understanding the predominance of such short-term and quantitative policy is essential for detailing how value is articulated. Chapter two reconsiders the two cultures debate. In contrast to the misrepresentative, yet pervasive, perception that the sciences and the humanities are fundamentally in opposition, I propose a more nuanced history of these disciplines. Chapter three addresses fictional representations of the humanities within literature in order to establish a vantage point from which to assess alternative routes for valuation beyond economic narratives. The final chapter scrutinises the rise of the impact criterion within research assessment and places it within a wider context of market-led cultural policy (1980-90s). This thesis argues that reflecting on Victorian legacies of economism and public accountability enables us to reconsider contemporary valuation culture in higher education. This analytical framework is of benefit to future academic studies interested in the marketisation and valuation of culture, alongside literary studies that focus on the relationship between higher education, the individual, and the state.
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Steinbach, Gabi, Michael Schreiber, Dennis Nissen, Manfred Albrecht, Ekaterina Novak, Pedro A. Sánchez, Sofia S. Kantorovich, Sibylle Gemming, and Artur Erbe. "Field-responsive colloidal assemblies defined by magnetic anisotropy." American Physical Society, 2019. https://monarch.qucosa.de/id/qucosa%3A70641.

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Particle dispersions provide a promising tool for the engineering of functional materials that exploit self-assembly of complex structures. Dispersion made from magnetic colloidal particles is a great choice; they are biocompatible and remotely controllable among many other advantages. However, their dominating dipolar interaction typically limits structural complexity to linear arrangements. This paper shows how a magnetostatic equilibrium state with noncollinear arrangement of the magnetic moments, as reported for ferromagnetic Janus particles, enables the controlled self-organization of diverse structures in two dimensions via constant and low-frequency external magnetic fields. Branched clusters of staggered chains, compact clusters, linear chains, and dispersed single particles can be formed and interconverted reversibly in a controlled way. The structural diversity is a consequence of both the inhomogeneity and the spatial extension of the magnetization distribution inside the particles. We draw this conclusion from calculations based on a model of spheres with multiple shifted dipoles. The results demonstrate that fundamentally new possibilities for responsive magnetic materials can arise from interactions between particles with a spatially extended, anisotropic magnetization distribution.
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Marre, Dirk. "Untersuchungen zum Vorkommen und Transportverhalten von Partikeln in Grundwässern und Abschätzung ihrer Relevanz für den Schadstofftransport." Doctoral thesis, Technische Universität Dresden, 2003. https://tud.qucosa.de/id/qucosa%3A24354.

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Im Grundwasser mobile Feststoff-Partikel stehen im Verdacht, den Transport schwerlöslicher Schadstoffe zu begünstigen. Die Partikel-Konzentration im Wasser lässt sich aber nur mittels einer aufwändigen Probenahme bestimmen. Vor diesem Hintergrund wurden im Rahmen dieser Arbeit Feld- und Laborversuche durchgeführt. In Feldversuchen zur Probenahme wurde festgestellt, dass für eine Stabilisierung der Partikel-Anzahl-Konzentration (CN in Partikel>Nachweisgrenze/L) die Dauer der Probenahme ausschlaggebend ist, nicht das insgesamt geförderte Volumen. Eine hohe Förderrate hat dabei nicht automatisch eine stärkere Mobilisierung von Partikeln aus dem Partikel-Depot im Umfeld der Messstelle zur Folge, wie es häufig postuliert wird. Die Gewinnung einer repräsentativen Partikelprobe macht eine Probenahme-Dauer von mindestens 5, häufig sogar über 10 oder 12 Stunden erforderlich. Empfehlungen zur Probenahme wurden erarbeitet. Es wurde aber festgestellt, dass sich stabilisierte Werte für CN als Funktion der Förderdauer (t in min) nach CN = a ? t^(-½) ungefähr abschätzen lassen, wenn der Parameter a über CN nach ca. 60 Minuten ermittelt wird. Bei Wässern mit Sauerstoff-Konzentrationen über ca. 1 mg/L kann überdies auch die Verteilung der Partikel auf einzelne Größenklassen bereits nach dieser Zeit ermittelt werden; bei sauerstoffärmeren Wässern verändert sie sich später noch. Angesichts einer starken Variation von CN einer Messstelle ist es generell aber nur möglich, eine Größenordnung für die Hintergrundkonzentration anzugeben. Von Messstelle zu Messstelle sind große Unterschiede bei CN festzustellen. Die Konzentration ist dabei nicht eindeutig abhängig von der Lithologie des Grundwasserleiters oder der Zusammensetzung des Grundwassers. Allerdings konnte eine schwache Korrelation mit dem Redox-Potential (Eh in mV) des Wassers gefunden werden (CN = 1,8?10^6?e^( 0,0087?Eh) [Partikel>2,58µm/L]; r² ≈ 0,46). Hierüber besteht die Möglichkeit, CN eines Grundwassers auch ohne Partikelmessung abzuschätzen. Insgesamt bewegen sich die Partikel-Massen-Konzentrationen (C in mg/L) der beprobten Wässer meist im Bereich von <1 mg/L, öfters sogar <0,1 mg/L, wenn die im Verlaufe von Probenahme und Messung ausgefällten Fe- und Mn-Oxide nicht berücksichtigt werden. Solche Konzentrationen sind vermutlich kaum in der Lage, relevante Mengen selbst sehr hydrophober Schadstoffen aufzunehmen und zu transportieren. Versuche mit Phenanthren ergaben zudem, dass es anscheinend weniger an bereits in Suspension befindliche Partikel sorbiert, sondern vielmehr in sorbiertem oder kristallinen Zustand aus dem Depot erodiert wird. In Laborversuchen wurde weiter gezeigt, dass in natürlichen Sedimenten ein großes Depot mobilisierbarer Partikel vorhanden ist, das Partikel über einen sehr langen Zeitraum kontinuierlich abgeben kann. Durchbruchsversuche ergaben außerdem, dass ein Großteil zugegebener Partikel bei der Passage durch eine Sedimentprobe zurückgehalten und nur sehr allmählich wieder abgegeben wird. Allerdings war auch ein schneller (präferentieller) Durchbruch zu verzeichnen. In Modellrechnungen konnte gezeigt werden, dass sich ein solcher Partikeltransport weder über eine Filterfunktion noch über die Transportgleichung zufrieden stellend berechnen lässt. Daher ist es nötig, einerseits einen bevorzugten Transport und andererseits eine starke Retardation zu berücksichtigen. Letzteres kann am besten über verschiedene Retardationsfaktoren oder ein dynamisches Partikel-Depot mit Anlagerungs- und Ablösungskonstanten geschehen.
Solid particles that are mobile in groundwater are suspected to enhance the transport of hardly soluble contaminants. But particle concentrations in water can only be measured using time-consuming sampling-procedures. On this background field- and laboratory-experiments were conducted in this work. In field experiments on sampling it turned out, that sampling time is crucial for stabilizing particle number-concentration (CN in particles>detection limit/L), not the volume sampled. A high sampling rate does not -as often argued- automatically result into higher mobilization of particles from the particle-depot in the vicinity of the sampling-well. Obtaining a representative particle sample requires a sampling-time of at least 5, often even more than 10 or 12 hours. In this work recommendations on sampling are given. It was noticed that stabilized values of CN can be estimated as function of sampling time (t in min) by CN = A ? t^(-½), if parameter A is calculated using CN after about 60 minutes. In waters having oxygen-concentrations above approximately 1 mg/L even distribution of the particles into size classes can be estimated after this time; in oxygen-poor waters size-distributions stabilized much later. Because of strong variations of CN in a single measuring well it is generally only possible to give the magnitude of the background-particle-concentration. But among several measuring wells CN may differ by several magnitudes. The concentrations do neither definitely depend upon the lithology of the aquifer nor on the groundwater-composition. But a weak correlation to the redox-potential (Eh in mV) can be found (CN = 1.8 ? 10^6 ? e^( 0.0087 ? Eh) [particles>2.58µm/L]; r² ≈ 0,46). Using this connection it is possible to estimate a magnitude of CN of a groundwater without even measuring particles. Over all particle mass-concentrations (C in mg/L) of all sampled groundwaters were almost always <1 mg/L, often even <0.1 mg/L, at least if iron- and manganese-oxides that precipitated during measurements were ignored. Such particle concentrations are probably hardly capable of adsorbing and carrying relevant amounts of contaminants, even very hydrophobic ones. Experiments using phenanthrene in contaminated sand additionally showed that it is probably hardly adsorbed onto already suspended particles, but mostly eroded from the particle depot in adsorbed or crystalline state. In laboratory experiments it was further shown that there is a huge depot of mobilizable particles in natural sediments that can continually release particles over a very long period of time. Break-through-experiments showed in addition that a large part of particles fed into the system are retained during the passage through a sediment sample and that they are re-released only very slowly. However, there also was a fast (preferential) break-through. In model calculations it could be shown that such a particle transport can neither be sufficiently described by the filter-function nor by the transport equation. Because of that it is necessary to take into consideration a preferential transport on the one hand and a strong retardation on the other. The last one can at the best be described by several retardation-factors or a dynamic particle-depot having constant attachment- and detachment rates.
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Steinbach, Gabi. "Ferromagnetic colloidal particles with anisotropic magnetization distribution: self-assembly and response to magnetic fields." Doctoral thesis, Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-207403.

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Systems of interacting colloidal particles are ideal tools for studies of pattern formation and collective non-equilibrium dynamics on the mesoscopic scale. These processes are governed by the interaction between the particles, which can be tuned by sophisticated fabrication. In this thesis, self-assembly of artificially designed magnetic spheres dispersed in water has been studied via video microscopy. The particles are based on silica microspheres with hemispherical ferromagnetic coating of [Co/Pd] multilayers with perpendicular magnetic anisotropy. These particles are exceptional in that they exhibit an off-centered net magnetic moment and yet obey rotational and mirror symmetry. It has been demonstrated how these magnetic properties provide innovative flexibility in pattern formation and collective dynamics based on magnetostatic interactions on the mesoscopic scale. The results are supported by analytical and numerical calculations of interacting spheres with radially shifted point dipoles (sd-particles). In two dimensions, the particles spontaneously self-assemble into branched structures as a result of a bistable assembly behavior where neighboring particles exhibit a non-collinear magnetic orientation. It has been shown that these features, which are atypical for homogeneous systems of magnetic particles, can be reproduced by simulation. It employs a theoretical model of a sphere that contains a distribution of three radially shifted point dipoles in analogy to the magnetization distribution in the coated particles. The stability of the assembly has been examined further by external manipulation using optical tweezers and homogeneous magnetic fields. A rich variety of stable structures with diverse spatial and magnetic ordering has been found. Particularly, the collective alignment of the specially designed particles in external fields opens completely new possibilities for the remote control over reversible pattern formation on the micrometer scale. In time-dependent fields, the collective dynamics of the anisotropic particles has revealed a novel approach for magnetically actuated translation. The variety of stable structures particularly enables control over this motion
Kolloidale Suspensionen sind geeignete Systeme zur Untersuchung von Strukturbildung und kollektiver Nichtgleichgewichtsdynamik in mesoskopischen Größenskalen. Diese Vorgänge werden durch die Wechselwirkung zwischen den Teilchen bestimmt, welche durch geeignete Partikelherstellung angepasst werden kann. In der vorliegenden Arbeit wird ein System von künstlich hergestellten magnetischen Partikelsuspensionen mittels Videomikroskopie untersucht. Quarzglas-Mikrokugeln wurden halbseitig mit einer ferromagnetischen Dünnschicht aus [Co/Pd] Multilagen mit senkrechter Anisotropie beschichtet. Solche Partikel sind ausgezeichnet durch ein resultierendes magnetisches Moment mit Rotations- und Spiegelsymmterie, welches zusätzlich vom Mittelpunkt der Kugel verschoben ist. Die vorliegende Arbeit zeigt, dass diese Besonderheit zu einer bisher unbekannten Flexibilität bei der mesoskopischen Strukturbildung und der kollektiven Dynamik auf der Basis magnetostatischer Wechselwirkung führt. Die vorgestellten Ergebnisse werden durch analytische und numerische Berechnungen unterstützt, denen ein Modell einer idealen Kugel mit verschobenem Dipol zugrunde liegt. Die zweidimensionale Selbstanordnung der Partikel zeigt experimentell zwei stabile Formen der Verknüpfung, welche zu verzweigten Strukturen mit unterschiedlich magnetischer Ausrichtung benachbarter Partikel führen. Diese für ein homogenenes System magnetischer Partikel außergewöhnlichen Eigenschaften konnten in Simulationen durch ein Modellsystem aus Kugeln mit drei verschobenen Punktdipolen reproduziert werden. Darüber hinaus wurde die spontante Anordnung unter externer Manipulation mittels optischer Pinzette und magnetischen Feldern untersucht. Es konnte eine Vielfalt an stabilen Strukturen mit verschiedenen magnetischen und strukturellen Anordnungen gefunden werden. Insbesondere die kollektive Ausrichtung dieser Partikel in externen Feldern eröffnet neuartige Möglichkeiten, kontrolliert und reversibel Mikrostrukturen zu erzeugen. In zeitabhängigen Feldern zeigen die anisotropen Partikel zusätzlich eine kollektive Dynamik welche eine neue Möglichkeit zum magnetischen Antrieb von Partikelagglomeraten eröffnet. Die Vielfalt der möglichen stabilen Strukturen erlaubt es in besonderer Weise diese Bewegung zu steuern
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13

Aland, Sebastian. "Modelling of two-phase flow with surface active particles." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-92397.

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Kolloidpartikel die von zwei nicht mischbaren Fluiden benetzt werden, tendieren dazu sich an der fluiden Grenzfläche aufzuhalten um die Oberflächenspannung zu minimieren. Bei genügender Anzahl solcher Kolloide werden diese zusammengedrückt und lassen die fluide Grenzfläche erstarren. Das gesamte System aus Fluiden und Kolloiden bildet dann eine spezielle Emulsion mit interessanten Eigenschaften. In dieser Arbeit wird ein kontinuum Model für solche Systeme entwickelt, basierend auf den Prinzipien der Massenerhaltung und der themodynamischen Konsistenz. Dabei wird die makroskopische Zwei-Phasen-Strömung durch eine Navier-Stokes Cahn-Hilliard Gleichung modelliert und die mikroskopischen Partikel an der fluiden Grenzfläche durch einen Phase-Field-Crystal Ansatz beschrieben. Zur Evaluation des verwendeten Strömungsmodells wird ein Test verschiedener Navier-Stokes Cahn-Hilliard Modelle anhand eines bekannten Benchmark Szenarios durchgeführt. Die Ergebnisse werden mit denen von anderen Methoden zur Simulation von Zwei-Phasen-Strömungen verglichen. Desweiteren wird eine neue Methode zur Simulation von Zwei-Phasen-Strömungen in komplexen Gebieten vorgestellt. Dabei wird die komplexe Geometrie implizit durch eine Phasenfeldvariable beschrieben, welche die charakteristische Funktion des Gebietes approximiert. Die Strömungsgleichungen werden dementsprechend so umformuliert, dass sie in einem größeren und einfacheren Gebiet gelten, wobei die Randbedingungen implizit durch zusätzliche Quellterme eingebracht werden. Zur Einarbeitung der Oberflächenkolloide in das Strömungsmodell wird schließlich die Variation der freien Energie des Gesamtsystems betrachtet. Dabei wird die Energie der Partikel durch die Phase-Field-Crystal Energie approximiert und die Energie der Oberfläche durch die Ginzburg-Landau Energie. Eine Variation der Gesamtenergie liefert dann die Phase-Field-Crystal Gleichung und die Navier-Stokes Cahn-Hilliard Gleichungen mit zusätzlichen elastischen Spannunngen. Zur Validierung des Ansatzes wird auch eine sharp interface Version der Gleichungen hergeleitet und mit der zuvor hergeleiteten diffuse interface Version abgeglichen. Die Diskretisierung der erhaltenen Gleichungen erfolgt durch Finiten Elemente in Kombination mit einem semi-impliziten Euler Verfahren. Durch numerische Simulationen wird die Anwendbarkeit des Modells gezeigt und bestätigt, dass die oberflächenaktiven Kolloide die fluide Grenzfläche hinreichend steif machen können um externen Kräften entgegenzuwirken und das gesamte System zu stabilisieren
Colloid particles that are partially wetted by two immiscible fluids can become confined to fluidfluid interfaces. At sufficiently high volume fractions, the colloids may jam and the interface may crystallize. The fluids together with the interfacial colloids compose an emulsion with interesting new properties and offer an important route to new soft materials. Based on the principles of mass conservation and thermodynamic consistency, we develop a continuum model for such systems which combines a Cahn-Hilliard-Navier-Stokes model for the macroscopic two-phase fluid system with a surface Phase-Field-Crystal model for the microscopic colloidal particles along the interface. We begin with validating the used flow model by testing different diffuse interface models on a benchmark configuration for a two-dimensional rising bubble and compare the results with reference solutions obtained by other two-phase flow models. Furthermore, we present a new method for simulating two-phase flows in complex geometries, taking into account contact lines separating immiscible incompressible components. In this approach, the complex geometry is described implicitly by introducing a new phase-field variable, which is a smooth approximation of the characteristic function of the complex domain. The fluid and component concentration equations are reformulated and solved in larger regular domain with the boundary conditions being implicitly modeled using source terms. Finally, we derive the thermodynamically consistent diffuse interface model for two-phase flow with interfacial particles by taking into account the surface energy and the energy associated with surface colloids from the surface PFC model. The resulting governing equations are the phase field crystal equations and Navier-Stokes Cahn-Hilliard equations with an additional elastic stress. To validate our approach, we derive a sharp interface model and show agreement with the diffuse interface model. We demonstrate the feasibility of the model and present numerical simulations that confirm the ability of the colloids to make the interface sufficiently rigid to resist external forces and to stabilize interfaces for long times
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14

Bartlová, Jana. "Návrh rekonstrukce dřevěných konstrukcí stávajícího objektu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227155.

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The content of this work was to carry out construction-technical survey of timber structures of the existing building in order to design an appropriate procedure for their reconstruction. The survey showed construction in an unsatisfactory to disrepair, so further work also includes the static calculation of new structures proposed instead of the current. Timber structure in the building has form of staircase, roof and ceiling construction. Newly designed the following types of stairs and roof trusses from which the lower belts are used as ceiling beams. The new proposal also includes possible roofing, roofing options, developed one of them. The work also includes drawings, bill of materials and cost estimate staircase structure and truss. Specialization in the field of civil engineering is represented by drawings of the new truss and passport (view of current state) whole object on parcel ST.74 / 1, land Tišnov (okr.Brno-venkov), the content of which was the basis for this work.
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15

Rosche, Christopher. "Optimierung der Fluoreszenzgraduierung von Polyelektrolyt-Multischichten auf kolloidalen Trägern für die Durchflusszytometrie." Doctoral thesis, 2011. https://ul.qucosa.de/id/qucosa%3A11628.

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Die Arbeit untersucht den Einfluss des pH - Wertes auf die Fluoreszenzintensität von Multischichtsystemen während des Beschichtungsvorgangs von Siliziumdioxidpartikeln mit kovalent an Polyallylaminhydrochlorid (PAH) gebundenem Rhodamin - B - Isothiocyanat. Durch eine konsequente Pufferung mit 2 -(N - Morpholino)ethansulfonsäure während der Beschichtung kann eine Verbesserung der Homogenität der Schichtbildung und eine Erhöhung der Fluoreszenzintensität erreicht werden. Außerdem liegt eine lineare Steigerung der Fluoreszenzintensität proportional zur Anzahl der fluoreszenten Schichten vor. Weiterhin sollen kolloidale Partikel unter konstanter Pufferung zusätzlich zu Rhodamin – B – Isothiocyanat mit an PAH – gebundenem Fluoresceinisothiocyanat beschichtet werden. Dieses Farbstoffpaar weist bei Annäherung eine Fluoreszenzsteigerung durch einen Fluoreszenzresonanzenergietransfer aus. Durch Variation von Schichtanzahl und Abstand wurden verschiedene Partikelpopulationen hergestellt, die sich in Ihrer Fluoreszenzintensität analog zu einem Bead Array Assay im Durchflusszytometer klar differenzieren lassen und dabei auch eine gleichmäßige Steigerung der Fluoreszenzintensität analog zur Anzahl der fluoreszenten Schichten aufweisen.
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16

Tzounis, Lazaros. "Glass and Jute fibers modified with CNT-based functional coatings for high performance composites." Doctoral thesis, 2011. https://tud.qucosa.de/id/qucosa%3A28116.

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Carbon nanotubes are known as one of the strongest materials in nature and since their discovery; they have triggered the scientific interest for fabricating multi-functional polymer composites. However, a well-known problem associated to the incorporation of nanoparticulate materials in polymer matrices is their tendency to agglomerate in order to reduce their surface energy, and the extreme increase of the polymer viscosities (i.e melts, solutions, etc), which makes it very difficult to process them. Polymers can be efficiently reinforced by fibers for applications where high strength and stiffness are required. Micro-scale short fiber reinforced polymer composites have been an alternative way to obtain fiber reinforced composites since the long fiber incorporation is a painful job and not always feasible and easy to produce composites in big scale. Therefore, use of long glass fibers as the support for depositing CNTs as well as CNTs+other kind of nanoparticles was made, and the resulting interfaces were investigated in detail by single fiber model composites. This approach can bring the CNT functionality, fiber strength and toughness to the final composite, and simultaneously alleviate the manufacturing process from increase of the polymer high viscosities. Finally, very logically the question of whether to improve or destroy the interface integrity comes before implementing the hybrid hierarchical reinforcements in bigger scales, and an output out of this work will be given. Furthermore, several information and functionalities arising from the CNTs at the interphase region will be elucidated like cure monitoring of the epoxy resin matrix, UV-sensing ability, and thermoelectric energy harvesting, giving rise to multi-functional structural composites. CNT-modified natural fibers also have been utillised to fabricate short fiber reinforced composites, and have shown a promising reinforcement effect due to the CNT nanostructured interfaces. The ‘interface’ in fiber reinforced polymer composites (FRPCs) is known as a very crucial parameter that has to be considered in the design of a composite with desired properties. Interfaces are often considered as surfaces however, they are in fact zones or areas with compositional, structural, and property gradients, typically varying from that of the fiber and the matrix material. Characterization of the mechanical properties of interfaces is necessary for understanding the mechanical behavior of scaled-up composites. In fact, the mechanical characteristics of a fiber/resin composite depend mainly on i) the mechanical properties of the component materials, ii) the surface of the fiber, and iii) the nature of the fiber/resin bonding as well as the mode of stress transfer at the interface. Among the many factors that govern the characteristics of composites involving a glass, carbon, natural or ceramic fiber, and a macromolecular matrix, the adhesion between fiber and matrix plays a predominant role. In specific, the stress transfer at the interface requires an efficient coupling between fiber and matrix. Therefore, it is important to optimize the interfacial bonding since a direct linkage between fiber and matrix gives rise to a rigid, low impact resistance composite material.
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