Hochschule für Life Sciences FHNW

Dauerhafte URI für den Bereichhttps://irf.fhnw.ch/handle/11654/22

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2014 - 20202

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Thema: search.filters.subject.660 - Technische Chemie

Bereich: Suchergebnisse

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    Publikation
    Thermokinetic model of hydroxylamine decomposition in the catalytic oxidation of ammonia with titanium silicalite-1
    (Hochschule für Life Sciences FHNW, 23.10.2020) Walthert, Florian; Zogg, Andreas; Fabian Meemken Lonza
    Hydroxylamine is a key molecule for some important chemical processes. An example is the synthesis of ε-caprolactam, which is required for the production of Nylon. Since hydroxylamine decomposes thermally, its transport and storage are problematic. It is also problematic for the synthesis of hydroxylamine from ammonia with titanium silicalite-1. The goal of this study was to investigate the exothermic decomposition reaction. The heat of the reaction was measured in multiple DSC experiments. During the decompo sition, vast quantities of gases are released. To measure the pressure rise, an explosion reactor was employed. Three reaction hypotheses have been tested. With the use of a mathematical model one hypothesis could be proven. The material in uence on the de composition reaction was examined for PEEK, stainless steel and hastelloy C22. From the DSC measurements, a descriptive model and isoconversional kinetics were obtained.
    11 - Studentische Arbeit
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    Publikation
    Damping of selective-laser-melted NiTi for medical implants
    (Springer, 2014) de Wild, Michael; Meier, Fabian; Bormann, Therese; Howald, Chaim; Müller, Bert
    NiTi exhibits distinct damping properties associated with the martensite-austenite transformation. We fabricated net-shape NiTi parts layer-by-layer using a laser beam that locally melted the NiTi powder. The damping properties of such NiTi parts were analyzed by the decay of cantilever vibrations in comparison to conventionally prepared NiTi. The dynamic modulus as a function of the temperature was derived from the resonant frequency. We found that the two cantilevers showed a damping ratio of about 0.03 at temperatures below austenite start, maximal values of up to 0.04 in the transformation regions and low values of about 0.005 above austenite finish. The results indicate that selective-laser-melted NiTi qualifies for the fabrication of shock-absorbing medical implants in the same manner than conventionally produced NiTi.
    01A - Beitrag in wissenschaftlicher Zeitschrift