Performance analysis on percentage of wheel slip for a passenger car using GPS and wheel speed sensor

This thesis deals with the analysis on percentage of wheel slip for a passenger car using GPS and wheel speed sensor. The objective of this thesis is to analyze the percentage of wheel slip for a passenger car in a various velocity, road condition and driving mode. The thesis describes the post-processing method to analyze the percentage of wheel slip and identify the effective rolling radius and the longitudinal tire stiffness for maximum tire life and performance. Driving and braking behaviour of vehicle were both studied in this thesis for paved and unpaved sandy road condition which commonly the contributing factors to the wheel slip to occur. The data used for the analysis is obtained through experimental test using UMP Test Car which has been installed with Wheel Pulse Transducer, Global Positioning System and DEWESOFT software for data acquisition purpose. The post-processing method was performed using Flexpro and Microsoft Office Excel. The post-processing method to analyze the percentage of wheel slip was performed using the SAE definition of wheel slip and the percent error in the distance travel by the car between free rolling and actual condition. Finally, the longitudinal force, the effective rolling radius and the longitudinal tire stiffness was determined for both driving and braking maneuver of vehicle on paved and unpaved sandy road condition. From the results, it is observed that the percentage of wheel slip during driving maneuver is higher for unpaved sandy road condition compares to that the paved road. It is also observed that the longitudinal force of the tire is lower for unpaved sandy road compare to the paved road condition. The effective rolling radius of the tire during driving maneuver was determined to be lower compare to the free rolling radius of the tire. During braking manuever, the results show that the percentage of wheel slip is higher for unpaved sandy road compare to that for paved road condition. The longitudinal force and tire stiffness also observed lower for unpaved sandy road condition. The effective rolling radius of the tire during braking determined higher compared to that in the free rolling radius. The results concluded that the percentage of wheel slip is strongly dependent to the longitudinal force and the tire road friction. Therefore, effective rolling radius and longitudinal tire stiffness obtained can significantly use to improve tire design and construction. The results also can be use to improve the energy usage efficiency and fuel consumption of vehicle

apropos: [Perspektiverweiterung auf die Romania und darüber hinaus]

Vorwort zur Nummer 5Editoria

Quantum logic inspired techniques for spacetime-symmetry tests with (anti-)protons

Cosmological observations as well as theoretical approaches to physics beyond the standard model provide strong motivations for experimental tests of fundamental symmetries, such as CPT invariance. In this context, the availability of cold baryonic antimatter at CERN has opened an avenue for ultrahigh-precision comparisons of protons and antiprotons in Penning traps. This work discusses an experimental method inspired by quantum logic techniques that will improve particle localization and readout speed in such experiments. The method allows for sympathetic cooling of the (anti-)proton to its quantum-mechanical ground state as well as the readout of its spin alignment, replacing the commonly used continuous Stern–Gerlach effect. Both of these features are achieved through coupling to a laser-cooled 'logic' ion co-trapped in a double-well potential. This technique will boost the measurement sampling rate and will thus provide results with lower statistical uncertainty, contributing to stringent searches for time dependent variations in the data. Such measurements ultimately yield extremely high sensitivities to CPT violating coefficients acting on baryons in the standard-model extension, will allow the exploration of previously unmeasured types of symmetry violations, and will enable antimatter-based axion-like dark matter searches with improved mass resolution

11B-rich fluids in subduction zones: the role of antigorite dehydration in subducting slabs and boron isotope heterogeneity in the mantle

Serpentinites form by hydration of mantle peridotite and constitute the largest potential reservoir of fluid-mobile elements entering subduction zones. Isotope ratios of one such element, boron, distinguish fluid contributions from crustal versus serpentinite sources. Despite 85% of boron hosted within abyssal peridotite being lost at the onset of subduction at the lizardite-to-antigorite transition, a sufficient cargo of boron to account for the composition of island arc magma is retained (c. 7 μg g− 1, with a δ11B of + 22‰) until the down-going slab reaches the antigorite-out isograd. At this point a 11B-rich fluid, capable of providing the distinctive δ11B signature of island arc basalts, is released. Beyond the uniquely preserved antigorite-out isograd in serpentinites from Cerro del Almirez, Betic Cordillera, Spain, the prograde lithologies (antigorite–chlorite–orthopyroxene–olivine serpentinite, granofels-texture chlorite-harzburgite and spinifex-texture chlorite-harzburgite) have very different boron isotope signatures (δ11B = − 3 to + 6‰), but with no significant difference in boron concentration compared to the antigorite-serpentinite on the low P–T side of the isograd. 11B-rich fluid, which at least partly equilibrated with pelagic sediments, is implicated in the composition of these prograde lithologies, which dehydrated under open-system conditions. Serpentinite-hosted boron lost during the early stages of dehydration is readily incorporated into forearc peridotite. This, in turn, may be dragged to sub-arc depths as a result of subduction erosion and incorporated in a mélange comprising forearc serpentinite, altered oceanic crust and pelagic sediment. At the antigorite-out isograd it dehydrates, thus potentially providing an additional source of 11B-rich fluids

Biomechanical characteristics of bone substitute and screw osteosynthesis in stabilization of tibial depression fractures in osteoporotic bones

Das Ziel dieser Arbeit war die Untersuchung eines neuen bohrbaren Kalziumphosphatzements (Norian drillable Synthes GmbH) sowohl als alleiniges Knochenersatzmaterial als auch in Kombination mit Schrauben, die in Jail-Technik angebracht wurden bei der Versorgung von lateralen Tibiakopfimpressionsfrakturen. Laterale Tibiakopfimpressionsfrakturen wurden dafür in einem biomechanischen Frakturmodell künstlich erzeugt. Die Präparate wurden mit Knochenersatzmaterial (Gruppe 1), Knochenersatzmaterial mit zusätzlichen vier Schrauben in Jail-Technik (Gruppe 2) oder lediglich mit vier Schrauben (Gruppe 3) stabilisiert. Anschließend wurde das Einsinken des Knochens (Displacement) unter zyklischer Belastung sowie Steifigkeit und Maximalbelastung in load-to-failure-Tests ermittelt. Die Gruppen, die mit Knochenersatzmaterial versorgt wurden, zeigten unter zyklischer Belastung ein geringeres Displacement und eine höhere Steifigkeit. Die Maximalbelastung, der die Knochen in der Load-to-failure-Testung standhielten, war indes höher für die Gruppen, die mit Schrauben versorgt wurden. Fazit: Die Kombination aus Unterfütterung mit Knochenersatzmaterial und Stabilisierung mit Schrauben bietet die umfangreichste Versorgung bei lateralen Tibiakopfimpressionsfrakturen.The aim of this study was to investigate a new drillable calcium phosphate cement (Norian drillable Synthes GmbH) as a bone substitute either alone or in combination with screws in the jail technique with regard to the primary stability in lateral tibial depression fractures. Lateral depression fractures of the tibial plateau were created in a biomechanical fracture model. After reduction they were stabilised with bone substitute (group one), bone substitute with additional four screws in the jail technique (group two) or four screws only (group three). Displacement under cyclic loading, stiffness and maximum load in load-to-failure tests were determined. The groups with the bone substitute showed a lower displacement of the depressed articular fragment under cyclical loading and a higher stiffness. The maximum load was higher for the groups with screws. Conclusions: Only the combination of bone substitute and screws prevented secondary loss of reduction and, at the same time, provided enough stability under maximum load

Dimensionality of Motion and Binding Valency Govern Receptor–Ligand Kinetics As Revealed by Agent-Based Modeling

Mathematical modeling and computer simulations have become an integral part of modern biological research. The strength of theoretical approaches is in the simplification of complex biological systems. We here consider the general problem of receptor–ligand binding in the context of antibody–antigen binding. On the one hand, we establish a quantitative mapping between macroscopic binding rates of a deterministic differential equation model and their microscopic equivalents as obtained from simulating the spatiotemporal binding kinetics by stochastic agent-based models. On the other hand, we investigate the impact of various properties of B cell-derived receptors—such as their dimensionality of motion, morphology, and binding valency—on the receptor–ligand binding kinetics. To this end, we implemented an algorithm that simulates antigen binding by B cell-derived receptors with a Y-shaped morphology that can move in different dimensionalities, i.e., either as membrane-anchored receptors or as soluble receptors. The mapping of the macroscopic and microscopic binding rates allowed us to quantitatively compare different agent-based model variants for the different types of B cell-derived receptors. Our results indicate that the dimensionality of motion governs the binding kinetics and that this predominant impact is quantitatively compensated by the bivalency of these receptors

Offene Wissenschaft und Wissenschaftspraxis

Editorial Editoria

Editorial: apropos [Perspektiven auf die Romanistik]

EditorialEditoria

Varia(tionen), Inseln und neue Perspektiven

Vorwort zur vierten Ausgabe von apropos [Perspektiven auf die Romania]Editorial for the fourth issue of apropos [Perspektiven auf die Romania