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In the case of time-consuming or arduous activity the individual bone, modifications of the individual skeleton may occur. Specific activities or movements are predominantly responsible for these modifications and are likely to be carried out for long periods from a young age of the individual. One of these modifications is considered to be some of the so- called non-metric traits on the postcranial skeleton. Special attention is being paid to changes of the articulation facets and changes in some muscular or ligaments' binding areas which are considered to be possibly related to excessive physical stress, occurring through the lifetime (squatting position). With respect to the frequency of 30 postcranial non-metric traits 293 skeletal remains in the Great Moravian population from the settlement agglomeration Mikulčice-Valy (9th - 10th century) have been compared. The primary goal of this research was to determine the frequency of non-metric traits and to verify the relationship with sex - age or the potential laterality differences in the case of bilateral traits. Then, based on the variability of non-metric traits, two different socio-economic groups were compared - the castle (burial site III. church) and the hinterland (burial sites Prušánky and Josefov). The highest incidence of traits was...

En la actualidad, las grandes ciudades cuentan con diversos sistemas de transporte, sin embargo, la cantidad poblacional con el paso del tiempo va en aumento. Un claro ejemplo es la ciudad de Lima, que cuenta con más de 9,000,000 habitantes lo cual ocasiona problemas de aglomeración en sus sistemas de transporte, que por la excesiva demanda son saturados haciendo que los tiempos de espera lleguen a ser excesivos para los usuarios. Pese a ello, se pueden adoptar soluciones ingeniosas que no generen excesivos gastos económicos, utilizando medidas de gestión peatonal. El objetivo de esta investigación es mejorar el nivel de servicio peatonal mediante modelos en Vissim, la investigación está enfocada en la estación Naranjal del sistema BTR de Lima-Perú, Metropolitano, debido a que es una de las plataformas de embarque más críticas de la ciudad. Se modelaron tres escenarios con medidas de gestión peatonal: los semáforos peatonales, los separadores de flujo y los sistemas de alerta. La medida que tuvo mayor impacto en reducir la congestión peatonal fue el sistema de alerta con una densidad 1.06 m2/peatón teniendo un nivel de servicio E, una velocidad promedio de peatón de 5.80km/h y un tiempo de viaje máximo del peatón dentro de la estación de 261.37 segundos en el intervalo más crítico de la hora pico. En conclusión, de acuerdo con los resultados obtenidos, las tres medidas modeladas mejoran la densidad y velocidad peatonal, sin embargo, la que tuvo mayor impacto fue el uso de sistemas de alerta. / Currently, larges cities have various transportation systems, however, the population size over time is increasing. One clear example is the city of Lima, which has more tan 8,574,974 inhabitants and suffers from problems of agglomeration in its transport systems, which due to excessive demand are saturated and waiting times become excessive for users. Despite this, ingenious solutions can be adopted that don’ t generate excessive economic costs, using pedestrian management measures. The objective of this research is to improve the level of pedestrian service through models in Vissim, of the Naranjal station of Lima-Peru El Metropolitano, since it is one of the most critical boarding platforms in the city. Three scenarios with pedestrian management measures were modeled: pedestrian traffic lights, flow separator and warning systems. The result that had the greatest impact in reducing pedestrian congestion was the warning system with a density of 1.06 m2/pedestrian, having a service level E, and average pedestrian speed of 5.80 km/h and a maximun travel time of the pedestrians of 261.37 seconds in the most critical interval of the rush hour. In conclusion, accordin to the results obtained, the three modeled measures improve pedestrian density and speed, however, the one that has the greatest impact was the use of warning systems. / Tesis

En la presente investigación, se realiza una propuesta de mejora de la gestión de proveedores utilizando la técnica de clustering, con el fin de reducir los pedidos fuera de especificación de tiempo y calidad en una empresa de confección peruana. El problema se origina en la asignación de pedidos y en la tercerización de la producción, lo cual ocasiona hasta un 19% de incumplimiento en las especificaciones de los pedidos y representa hasta el 23% de pérdida sobre la utilidad neta de la empresa. El resultado del modelo de clúster, aplicado en los proveedores de servicio busca reducir la cantidad de pedidos atrasados de la empresa. Este modelo es validado mediante una simulación basada en “cómo hubiera sido” el resultado de aplicar la propuesta en el año anterior. En base al sector, se determinó que el incumplimiento se redujera hasta 5%; sin embargo, los resultados de la simulación en el escenario promedio indicaron 3.39% de incumplimiento. / In this research, a proposal is made to improve supplier management using the clustering technique, to reduce orders out of specification for time and quality in a Peruvian clothing company. The problem originates from the allocation of orders and the outsourcing of production, which causes up to 19% of non-compliance with the specifications of the orders and represents up to 23% of loss on the net profit of the company. The result of the cluster model, applied in service providers, seeks to reduce the number of backorders for the company. This model is validated through a simulation based on "how it would have been" the result of applying the proposal in the previous year. Based on the sector, it was determined that non-compliance was reduced to 5%; however, the simulation results in the average scenario indicated 3.39% non-compliance. / Trabajo de investigación

Das Hauptziel dieser Arbeit war die verfahrenstechnische, tribologische und konstruktive Optimierung einer Kompaktieranlage für Si-Pulver mit spezifischer Clusterstruktur und einer sehr geringen Schüttdichte von ca. 0,05 g/cm³. Die Steigerung der Kompaktatrohdichte auf >0,5 g/cm³ und die Erhöhung der Standzeit der keramischen Walzenbelegung unter Vermeidung des Fremdstoffeintrags in das Si-Pulver sind die wichtigsten Optimierungsziele. Eine Mehrfachverdichtung des Pulvers erweist sich als positiv für den Dichtewert. Die Beseitigung der Clusterstruktur durch Intensivmahlung sowie die Steigerung der Primärpartikelgröße des Pulvers führt ebenfalls zum Anstieg der Kompaktatrohdichte. Zum Verschleißschutz im Bereich der Stopfschnecke eignet sich eine DLC-Beschichtung (a-C:H:X) auf plasmanitriertem Stahl X5CrNi18-10. Herzbleche aus Zikonoxid und eine Walzenbelegung aus Siliziumnitrid sind beim Einsatz des Abrasivs Si-Pulver aus tribologischer Sicht am besten. Die Spannungsanalyse mittels FEM ist die Basis zur Ermittlung der optimalen Walzengeometrie und bestätigt das Siliziumnitrid als Walzenwerkstoff für den Verschleißschutz.

Avec la réduction de taille des composants microélectroniques, le monosiliciure de nickel (NiSi) a été largement utilisé dans les transistors CMOS (Complementary-Metal-Oxide-Semiconductor) en tant que contacts pour les sources, drains et grilles. Cependant, NiSi se dégrade lors du recuit à haute température. Il apparait essentiel d'étudier la séquence de formation de phases et la stabilité du monosilicide en présence d’éléments d'alliage. Les réactions à l'état solide entre des films de Ni allié en W et/ou Pt et un substrat de Si ont été étudiées principalement par diffraction des rayons X (DRX) in-situ et sonde atomique tomographique (SAT). L'analyse combinatoire de la réaction entre des films Ni avec différents composition gradients et le Si a permis de comprendre la séquence de formation. Les concentrations des éléments d'alliage (W et Pt) ont un impact significatif sur la séquence de formation des siliciures de Ni et sur la cinétique de formation des phases. Le mécanisme d'agglomération des films minces de NiSi a également été étudié au cours de cette thèse. Un film de Ni pur de 15 nm a été déposé sur un substrat de Si enrichi de multicouches de Si isotopique. Des analyses SAT ont été effectuées sur l'échantillon de Ni/Si (isotope) après un recuit à 600°C. En observant la distribution des isotopes de Si, un mécanisme d'agglomération de NiSi a été proposé selon que les isotopes de Si restent sous forme de multicouches ou qu'ils se mélangent. Cette étude rendue possible grâce à la capacité unique de la SAT d'observer les isotopes en 3D et à l'échelle atomique apporte une meilleure compréhension de l'agglomération de films minces poly-cristallin d'intermétallique / With the downscaling of microelectronic devices, NiSi has been widely used in complementary-metal-oxide-semiconductor (CMOS) transistors as contact on source, drain and gate. However, NiSi suffers from degradation upon annealing at high temperatures. Adding alloying elements is an effective method to increase the stability of nickel monosilicide but the formation sequence of Ni silicides is substantially modified. Therefore, the studies of the phase formation sequence and the stability of monosilicide are of great importance.The solid-state reactions between Ni films alloyed with W and/or Pt and Si substrates were studied mainly by in-situ X-ray diffraction (XRD) and atom probe tomography (APT) using combinatorial analysis of co-deposited gradient films. The phase sequence was monitored by in-situ XRD and APT was used to examine the silicides and reveal the redistribution of alloying elements. The content of alloying elements (W and Pt) has a large impact on the phase sequence of Ni silicides and the kinetics of phase formation. The basic agglomeration mechanism of NiSi thin films was studied. A 15nm pure Ni film was deposited on a Si substrate enriched with isotope multilayers. APT analyses were performed on the sample of Ni/Si (isotope) after an annealing at 600°C. By observing the distribution of Si isotopes (30Si, 29Si and 28Si), whether they maintain a multilayer structure or are mixed together, a mechanism of the agglomeration of NiSi was proposed. This was possible because of the unique capability of APT to observe isotopes in 3D at the atomic scale and it allows a better understanding and to control of the agglomeration of poly-crystalline compound thin films

Addition of nano particles to cooling fluids has shown marked improvement in the heat transfer capabilities. Nanofluids, liquids that contain dispersed nanoparticles, are an emerging class of fluids that have great potential in many applications. There is a need to understand the fundamental behavior of nano dispersed particles with respect to their agglomeration characteristics and how it relates to the heat transfer capability. Such an understanding is important for the development and commercialization of nanofluids. In this work, the stability of nano particles was studied by measuring the zeta potential of colloidal particles, particle concentration and size. Two different sizes of silica nano particles, 10 nm and 20 nm are used in this investigation at 0.2 vol. % and 0.5 vol. % concentrations. The measurements were made in deionized (DI) water, buffer solutions at various pH, DI water plus HCl acid solution (acidic pH) and DI water plus NaOH solution (basic pH). The stability or instability of silica dispersions in these solutions was related to the zeta potential of colloidal particles and confirmed by particle sizing measurements and independently by TEM observations. Low zeta potentials resulted in agglomeration as expected and the measured particle size was greater. The heat transfer characteristics of stable or unstable silica dispersions using the above solutions were experimentally determined by measuring heat flux as a function of temperature differential between a nichrome wire and the surrounding fluid. These experiments allowed the determination of the critical heat flux (CHF), which was then related to the dispersion characteristics of the nanosilica in various fluids described above. The thickness of the diffuse layer on nano particles was computed and experimentally confirmed in selected conditions for which there was no agglomeration. As the thickness of the diffuse layer decreased due to the increase in salt content or the ionic content, the electrostatic force of repulsion cease to exist and Van der Waal's force of agglomeration prevailed causing the particles to agglomerate affecting the CHF. The 10nm size silica particle dispersions showed better heat transfer characteristics compared to 20nm dispersion. It was also observed that at low zeta potential values, where agglomeration prevailed in the dispersion, the silica nano particles had a tendency to deposit on the nickel chromium wire used in CHF experiments. The thickness of the deposition was measured and the results show that with a very high deposition, CHF is enhanced due to the porosity on the wire. The 10nm size silica particles show higher CHF compared to 20nm silica particles. In addition, for both 10nm and 20nm silica particles, 0.5 vol. % concentration yielded higher heat transfer compared to 0.2 vol. % concentration. It is believed that although CHF is significantly increased with nano silica containing fluids compared to pure fluids, formation of particle clusters in unstable slurries will lead to detrimental long time performance, compared to that with stable silica dispersions.

Acoustic levitation permits the study of droplet dynamics without the effects of surface interactions present in other techniques such as pendant droplet methods. Despite the complexities of the interactions of the acoustic field with the suspended droplet, acoustic levitation provides distinct advantages of controlling morphology of droplets with nanosuspensions post precipitation. Droplet morphology is controlled by vaporization, deformation and agglomeration of nanoparticles, and therefore their respective timescales are important to control the final shape. The balance of forces acting on the droplet, such as the acoustic pressure and surface tension, determine the geometry of the levitated droplet. Thus, the morphology of the resultant structure can be controlled by manipulating the amplitude of the levitator and the fluid properties of the precursor nanosuspensions. The interface area in colloidal nanosuspensions is very large even at low particle concentrations. The effects of the presence of this interface have large influence in the properties of the solution even at low concentrations. This thesis focuses on the dynamics of particle agglomeration in acoustically levitated evaporating nanofluid droplets leading to shell structure formation. These experiments were performed by suspending 500µm droplets in a pressure node of a standing acoustic wave in a levitator and heating them using a carbon dioxide laser. These radiatively heated functional droplets exhibit three distinct stages, namely, pure evaporation, agglomeration and structure formation. The temporal history of the droplet surface temperature shows two inflection points. Morphology and final precipitation structures of levitated droplets are due to competing mechanisms of particle agglomeration, evaporation and shape deformation. This thesis provides iv a detailed analysis for each process and proposes two important timescales for evaporation and agglomeration that determine the final diameter of the structure formed. It is seen that both agglomeration and evaporation timescales are similar functions of acoustic amplitude (sound pressure level), droplet size, viscosity and density. However it is shown that while the agglomeration timescale decreases with initial particle concentration, the evaporation timescale shows the opposite trend. The final normalized diameter hence can be shown to be dependent solely on the ratio of agglomeration to evaporation timescales for all concentrations and acoustic amplitudes. The experiments were conducted with 10nm silica, 20nm silica, 20nm alumina and 50nm alumina solutions. The structures exhibit various aspect ratios (bowls, rings, spheroids) which depend on the ratio of the deformation timescale (tdef) and the agglomeration timescale (tg). For tdef

Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV- screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and + 4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the existing literature is confined to short term studies pertaining to synthesis and property evaluation. Having understood the need for a comprehensive understanding of the CNP suspensions, this dissertation is primarily aimed at understanding the behavior of CNPs in various chemical and physical environments. We have synthesized CNPs in the absence of any surfactants at room temperature and studied the aging characteristics. After gaining some understanding about the behavior of this functional oxide, the synthesis environment and aging temperature were varied, and their affects were carefully analyzed using various materials analysis techniques such as high resolution transmission electron microscopy (HRTEM), UV-Visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). When the CNPs were aged at room temperature in as-synthesized condition, they were observed to spontaneously assemble and evolve as fractal superoctahedral structures. The reasons for this unique polycrystalline morphology were attributed to the symmetry driven assembly of the individual truncated octahedral and octahedral seed of the ceria. HRTEM and Fast Fourier Transform (FFT) analyses were used to explain the agglomeration behavior and evolution of the octahedral morphology. Some of the observations were supported by molecular dynamic simulations. Poly (ethylene glycol) (PEG) and ethylene glycol (EG) were used to control the kinetics of this morphology evolution. The ability to control the agglomeration of CNPs in these media stems from the lower dielectric constant and an increased viscosity of the EG and PEG based solvents. CNPs when synthesized and aged in frozen conditions, i.e. in ice, were found to form one dimensional, high aspect ratio structures. A careful analysis has provided some evidence that the CNPs use the porous channels in ice as a template and undergo oriented attachment to form nanorods. When the aging treatment was done near freezing temperature in solution, the nanorods were not observed, confirming the role of channels in ice. When synthesized in aqueous media such as DI water, PEG and EG; CNPs were observed to exhibit a reversible oxidation state switching between +3 and +4. Band gap values were computed from the optical absorption data. The changes in the band gap values observed were attributed to the changes in the oxidation state of CNPs as opposed to the quantum confinement effects, as expected in other nanoparticle systems. The work presented in this dissertation demonstrates, with evidence, that in order to obtain a comprehensive understanding of the properties of nanoscale materials it is of paramount importance to monitor their behavior over relatively longer periods of time under various ambient environments. While the solution based techniques offer a versatility and low cost route to study the fundamental properties of nanomaterials, they suffer some inherent problems such as precursor contamination and uncontrolled chemical reactions. Especially when analyzing the behavior of ceria-based materials for applications like solid oxide fuel cells, a great control in the density and crystalline quality are desired. In order to achieve this, as a first step pure ceria thin films were synthesized using oxygen plasma assisted molecular beam epitaxy (OPA-MBE). The ceria films were analyzed using various in situ and ex situ techniques to study the crystal structure, growth mode and epitaxial quality of the films. It was observed that the epitaxial orientation of the ceria films could be tuned by varying the deposition rate. When the films were grown at low deposition rate (< 8 Å/min) ceria films with epitaxial (200) orientation were observed where as the films grown at high deposition rates (up to 30 Å/min) showed (111) orientation. Theoretical simulations were used to confirm some of the experimental facts observed in both nanoparticles and thin films.

In dieser Arbeit wird eine umfassende Untersuchung von Clustern vorgestellt, wobei der Schwerpunkt auf dem Einfluss von Quellendruck, Temperatur und Agglomerationszustand auf die erzeugten Cluster liegt. Die neutralen Cluster werden durch Überschallstrahl-Expansion von Ar und CO2 in einem weniger untersuchten Bereich von Quellendrücken und -temperaturen erzeugt und anschließend durch Ultrahoch-Rayleigh-Streuungsmessungen charakterisiert. Die Analyse zeigt, dass das bekannte empirische Skalierungsgesetz möglicherweise nicht genau genug ist, wenn die Clustergrößen in realen Systemen einen breiteren Bereich abdecken. Ein wichtiger Schritt ist der Übergang von Ar als nahezu ideales Gas zu CO2 als reales System. Um zu beurteilen, ob die Werte der mittleren Clustergrößen aussagekräftig sind, wird in dieser Arbeit ein auf den experimentellen Ergebnissen basierendes Modell vorgeschlagen, das eine geeignete Position der Laser-Cluster-Wechselwirkungsregion im kollisionsfreien Bereich des Molekularstrahls bestimmt. Die geringe zeitliche Auflösung des mit dem Oszilloskop erfassten Signals führt zur Anwendung der Photonenzählung, die eine höhere Nachweisempfindlichkeit bietet. Im Falle von Ar-Clustern zeigt diese Methode die Übereinstimmung des Verhaltens mit den bekannten theoretischen Berechnungen. Die Analyse der relativen mittleren CO2-Clustergrößen zeigt dagegen, dass die theoretische Skalierung für Cluster, die sich aus Flüssigkeiten mit hoher Dichte bilden, nicht gut geeignet ist. Die relative mittlere Größe kleiner und besonders großer Cluster ermöglicht die Unterscheidung zwischen Clustern, die durch Expansion von der gasförmigen oder flüssigen Seite des kritischen Punktes erzeugt werden, und einem Zwischenbereich, in dem die Expansion die überkritischen gasförmigen und flüssigen Bereiche passiert. Bei Messungen in der Nähe der Widom-Linie zeigen zwei verschiedene gemessene und berechnete Skalierungsgesetze einen scharfen Übergang beim Überschreiten dieser Linie. / This thesis presents a comprehensive study of clusters with a focus on the influence of the source pressure, temperature, and agglomeration state on the generated clusters. The neutral clusters are generated by supersonic jet expansion of Ar and CO2 applying a less-studied range of source pressures and source temperatures and then characterized by ultra-high Rayleigh scattering measurements. The analysis indicates that the known empirical scaling law may lack sufficient accuracy when cluster sizes cover a broader range in real systems. An important step is moving from Ar as a near-ideal gas to CO2 as a real system. To evaluate whether the values of the mean cluster sizes are meaningful, in this thesis, a model based on the experimental results is proposed, which determines an appropriate position of the laser-cluster interaction region in the collisionless domain of the molecular beam. The low temporal resolution of the detected signal via oscilloscope leads to the application of photon counting that provides a higher detection sensitivity. In the case of Ar clusters, this method reveals the compliance of the behavior with the known theoretical calculations. The analysis of the relative mean CO2 cluster sizes, in contrast, indicate that the theoretical scaling does not suit well for clusters formed from the high-density fluids. The relative mean size of small and extra-large clusters enables the distinction of the clusters generated via expansion from the gas or the liquid side of the critical point and an intermediate regime where the expansion passes the supercritical gas-like and liquid-like regions. In measurements at conditions near the Widom line, two different measured and calculated scaling laws reveal a sharp transition on crossing it.