Magnetic Hybrid-Materials

Externally tunable properties allow for new applications of suspensions of micro- and nanoparticles in sensors and actuators in technical and medical applications. By means of easy to generate and control magnetic fields, fluids inside of matrices are studied. This monnograph delivers the latest insigths into multi-scale modelling, manufacturing and application of those magnetic hybrid materials

Magnetic Hybrid-Materials

Externally tunable properties allow for new applications of suspensions of micro- and nanoparticles in sensors and actuators in technical and medical applications. By means of easy to generate and control magnetic fields, fluids inside of matrices are studied. This monnograph delivers the latest insigths into multi-scale modelling, manufacturing and application of those magnetic hybrid materials

Development of PVDF tactile dynamic sensing in a behaviour-based assembly robot

The research presented in this thesis focuses on the development of tactile event sig¬ nature sensors and their application, especially in reactive behaviour-based robotic assembly systems.In pursuit of practical and economic sensors for detecting part contact, the application ofPVDF (polyvinylidene fluoride) film, a mechanical vibration sensitive piezo material, is investigated. A Clunk Sensor is developed which remotely detects impact vibrations, and a Push Sensor is developed which senses small changes in the deformation of a compliant finger surface. The Push Sensor is further developed to provide some force direction and force pattern sensing capability.By being able to detect changes of state in an assembly, such as a change of contact force, an assembly robot can be well informed of current conditions. The complex structure of assembly tasks provides a rich context within which to interpret changes of state, so simple binary sensors can conveniently supply a lot more information than in the domain of mobile robots. Guarded motions, for example, which require sensing a change of state, have long been recognised as very useful in part mating tasks. Guarded motions are particularly well suited to be components of assembly behavioural modules.In behaviour-based robotic assembly systems, the high level planner is endowed with as little complexity as possible while the low level planning execution agent deals with actual sensing and action. Highly reactive execution agents can provide advantages by encapsulating low level sensing and action, hiding the details of sensori-motor complexity from the higher levels.Because behaviour-based assembly systems emphasise the utility of this kind of quali¬ tative state-change sensor (as opposed to sensors which measure physical quantities), the robustness and utility of the Push Sensor was tested in an experimental behaviourbased system. An experimental task of pushing a ring along a convoluted stiff wire is chosen, in which the tactile sensors developed here are aided by vision. Three differ¬ ent methods of combining these different sensors within the general behaviour-based paradigm are implemented and compared. This exercise confirms the robustness and utility of the PVDF-based tactile sensors. We argue that the comparison suggests that for behaviour-based assembly systems using multiple concurrent sensor systems, bottom-level motor control in terms of force or velocity would be more appropriate than positional control. Behaviour-based systems have traditionally tried to avoid symbolic knowledge. Considering this in the light of the above work, it was found useful to develop a taxonomy of type of knowledge and refine the prohibition

Proceedings of the NASA Conference on Space Telerobotics, volume 4

Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center

Surface-Mounted Metal-Organic Frameworks as the Platform for Surface Science: Photoreactivity, Electroreactivity, and Thermal Reactivity

Bisher haben Forscher Modellsysteme wie Einkristallmetalle oder Metalloxide entwickelt, um reale Pulversysteme besser zu verstehen. Es bestehen jedoch immer noch Fragen hinsichtlich der Oberflächenstruktur und Reaktivität von MOFs (Metall-organische Gerüstverbindungen). Glücklicherweise bieten oberflächenorientierte SURMOFs (surface-oriented SURMOFs) einen alternativen Ansatz für den Aufbau von Modellplattformen zur Untersuchung dieser grundlegenden Aspekte von MOFs. Diese Arbeit konzentriert sich auf die organische Photochemie, Elektrokatalyse und thermische Pyrolyse von MOFs aus einer physikalisch-chemischen Perspektive unter Verwendung von Oberflächenwissenschaftstechniken und SURMOF-Plattformen. Das Ziel dieser Arbeit besteht nicht nur darin, das Wissen über MOFs und SURMOFs zu erweitern, sondern auch die Leistungsfähigkeit von Oberflächenwissenschaftstechniken und -methoden im Bereich chemischer Reaktionen zu demonstrieren. Zu diesem Zweck verwendet die Arbeit eine hochmoderne UHV-IRRAS-Apparatur (Ultra-High-Vacuum Infrared Reflection Absorption Spectroscopy). Ein auf der Oberfläche montiertes MOF (SURMOF) Modellsystem mit Azid-Seitenketten wurde erfolgreich hergestellt und genau überwacht, um chemische Veränderungen während des Betriebs zu erfassen. Die umfassenden Ergebnisse, die durch die Kombination von IRRAS mit in situ XRD, MS und XPS erzielt wurden, zeigen, dass die Photoreaktion von Azid durch die Bildung von hochaktiven Nitren-Gruppen initiiert wird, die anschließend mit benachbarten C=C-Bindungen des Gerüsts reagieren und Pyrrol-Derivate durch intramolekulare Aminierung erzeugen. Ein hochwertiges ZIF-67-SURMOF wurde in einem Flüssigphasen-Schicht-für-Schicht-Verfahren hergestellt und erstmals in der Sauerstoffentwicklungskatalyse (OER) eingesetzt. Die katalytisch aktiven Spezies, CoOOH, in den SURMOF-Derivaten wurden identifiziert, was Einblicke in die Mechanismen der strukturellen Transformation und die Struktur-Leistung-Beziehungen bietet. Durch Zugabe von Ni und B wurde die Überspannung auf 375 mV bei 10 mA/cm2 reduziert. Zusätzlich wurden in situ IRRAS und XPS verwendet, um die strukturellen Übergänge von ZIF-67 zu kohlenstoffhaltigen Materialien mit Stickstoffelementen zu enthüllen. NEXAFS-Daten zeigen eine abschließende graphitische Struktur der kohlenstoffhaltigen Materialien nach Pyrolyse bei 900 K. Hoffentlich kann diese Arbeit das grundlegende Verständnis und die Anwendungsfelder von auf MOF und SURMOF basierenden Materialien erweitern

Technology for large space systems: A bibliography with indexes (supplement 22)

This bibliography lists 1077 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion

Space station systems: A bibliography with indexes (supplement 10)

This bibliography lists 1,422 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to researchers, designers and managers engaged in Space Station technology development and mission design. Coverage includes documents that define major systems and subsystems related to structures and dynamic control, electronics and power supplies, propulsion, and payload integration. In addition, orbital construction methods, servicing and support requirements, procedures and operations, and missions for the current and future Space Station are included

The 1994 Silver Anniversary of APOLLO 11: From the Moon to the Stars

This report summarizes the technology transfer, advanced studies, and research and technology efforts in progress at Marshall Space Flight Center (MSFC) in 1994