1,733 research outputs found

    Challenges and Lessons Learned From Resurrecting a Legacy Research Flight Controller

    Get PDF
    Resurrecting the legacy Inner Loop Thrust Vectoring research flight controller to investigate the tail shock region brought unique challenges. This report documents these challenges and lessons learned from a stability and controls perspective. The flight test approach for flight envelope expansion and probing tests, as well as limited flight test results, are presented. Recent advances in sonic boom reduction technology have contributed to a resurgent interest in civilian supersonic cruise flight. These advances have focused only on fore body shaping, however, and little, if any, experimental flight data are available to develop and validate design tools for the tail shock region. In January of 2009, the NASA Dryden Flight Research Center completed research flights to investigate the tail shock region of a highly modified F-15 aircraft by probing the shock waves around it, using another F-15 aircraft. To adjust the lift distribution and plume shape, a decade-old research flight controller from the Inner Loop Thrust Vectoring project was required. To investigate the tail shock region, the lift distribution was changed by adjusting the canard position, and the plume shape was changed by adjusting the nozzle area and thrust vectoring

    Sporadic porphyria cutanea tarda due to haemochromatosis

    Get PDF
    Haemochromatosis is a hereditary iron-overload syndrome caused by increased intestinal iron absorption and characterised by accumulation of potentially toxic iron in the tissues. Sometimes this disease presents as a cutanea porphyria. We describe a patient with joint complaints and blistering skin lesions on sun-exposed skin. After identifying the porphyria cutanea tarda by urine analysis we found that the serum activity of uroporphyrinogen decarboxylase (UROD) was normal, meaning a partial inactivation of UROD in liver tissue due to external factors. Further investigation showed the homozygous Cys282Tyr missense mutation and high levels of serum ferritin. It is important to recognise the symptoms of iron overloading at an early stage because hereditary haemochromatosis needs to be treated immediately. We therefore advocate routine sampling of ferritin levels in patients with unexplained joint complaints

    Largemouth bass (Micropterus salmoides Lacépède): reproduction management and larval rearing in Italy

    Get PDF
    Micropterus salmoides (Lacépède) was originally present into the waters of the eastern United States of America, northern Mexico and southern Canada. This species can be distinguished from the other black basses by the fact that its mouth extends to and beyond the edge of the eye and the first and the second dorsal fins are almost separated by a deep dip and there are no scales on the soft rayed of the second dorsal fin

    Largemouth bass (Micropterus salmoides Lacépède): results of farming trials

    Get PDF
    In the last years in the United States, the demand of largemouth bass (Micropterus salmoides) larger than the size usually produced for sport fishing purposes has increased. The growth phase is carried on in ponds, after having evaluated different strains (Williamson and Carmichael, 1990) using feeds for salmonids (Tidwell et al., 1996) supplemented with amino acids (Coyle et al., 2000). Also in Italy, the market currently requires largemouth bass of 300-500 g. This situation has induced one farmer to cooperate with our research centre and carried out trials to verify the possibility of rearing this fish, from the fingerling stage up to the size suitable for food, using the same farming techniques as those currently being applied in the United States (Davis and Lock, 1997)
    • …
    corecore