Return to Service of a Liquid Hydrogen Storage Sphere

One, of two, 850,000 gallon liquid hydrogen storage spheres, at NASA's Kennedy Space Center, was decommissioned in 2010. This tank had an abnormally high heat leak that was investigated and determined to be the result of a large void in the perlite insulation. The insulation void was subsequently filled, and the tank was refurbished for its planned use in the Space Launch Systems (SLS) program. Return to service of this tank began in December of 2017 with a partial liquid hydrogen fill. Since that time, routine measurement of the liquid level have been recorded in order to establish a new boiloff rate and associated heat leak. This data shows the perlite top off activities have resulted in a much reduced, and within design specification, heat leak

Return to Service of a Liquid Hydrogen Storage Sphere

One, of two, 850,000 gallon liquid hydrogen storage spheres, at NASA's Kennedy Space Center, was decommissioned in 2010. This tank had an abnormally high heat leak that was investigated and determined to be the result of a large void in the perlite insulation. The insulation void was subsequently filled, and the tank was refurbished for its planned use in the Space Launch Systems (SLS) program. Return to service of this tank began in December of 2017 with a partial liquid hydrogen fill. Since that time, routine measurement of the liquid level have been recorded in order to establish a new boiloff rate and associated heat leak. This data shows the perlite top off activities have resulted in a much reduced, and within design specification, heat leak

Influence of the vegetation structure on the nest-site selection of birds of prey in the March floodplain forests, Lower Austria

Zwischen Januar und Juli 2008 wurden im March-Auwald zwischen Hohenau und Drösing im niederösterreichischen Bezirk Gänserndorf (19,7 km2) systematisch Greifvogelhorste kartiert, und auf Besetzung und Bruterfolg kontrolliert. Im weitgehend geschlossenen Waldgebiet sind zwei unterschiedliche Forstwirtschaftsformen vorrangig. Der nördliche Teil wird als Hochwald (960 ha) geführt, der südliche Teil als Mittel- und Niederwald (1010 ha). Analysen zur Waldstruktur rund um jeden Horstplatz (Mikrohabitat, r=15 m, 706,5 m2), sowie zum Anteil verschiedener Biotoptypen im Kernbereich der Greifvogelreviere (Makrohabitat, r=250 m, 19,6 ha) geben Aufschluss, welche Faktoren die Verbreitung der Greifvögel in den March-Auen beeinflussen. Um einen repräsentativen Querschnitt des vorhandenen Strukturangebots zu erhalten, wurden die Erhebungen in gleicher Art auf 50 zufällig bestimmten Flächen wiederholt. Die erhobenen Daten zur Habitatwahl wurden in einem geographischen Informationssystem ausgewertet. Insgesamt wurden 167 Horste kartiert, davon waren 57 von Greifvögeln besetzt. Die häufigste Art ist der Mäusebussard (Buteo buteo) mit 34 besetzten Horsten, gefolgt von der Rohrweihe (Circus aeroginosus) mit 5-6 Brutpaaren. Der Rotmilanbestand (Milvus milvus) von 3 Brutpaaren ist von nationaler Bedeutung. Schwarzmilan (Milvus migrans), Wespenbussard (Pernis apivorus) und Habicht (Accipiter gentilis) sind mit je 3 Brutpaaren, Turmfalke (Falco tinnunculus) und Baumfalke (Falco subbuteo) mit je 2 Brutpaaren vertreten. Seit 2002 brütet auch ein Seeadlerpaar (Haliaeetus albicilla) erfolgreich im Untersuchungsgebiet. Zusätzlich brüten Sperber (Accipiter nisus), Sakerfalke (Falco cherrug) und Kaiseradler (Aquila heliaca) in den umliegenden Flächen. Die Greifvogelbestände sind seit den 1990er Jahren weitgehend stabil. Allein beim Mäusebussard ist eine Bestandszunahme zu verzeichnen, die auf natürliche Schwankungen entsprechend der Mäusegradation und auf eine Entdynamisierung der Au zurückzuführen ist. Die vorgefundenen Siedlungsdichten der Greifvögel an der March sind auch in einem mitteleuropäischen Vergleich als hoch einzustufen. Die Habitatanalyse hat gezeigt, dass Greifvögel Stieleichenüberhälter und zusammenhängende, alte Pappelkulturen als Horstbäume bevorzugen. Diese Baumarten finden sich im Mittelwald häufiger als im Hochwald. Auch sind im Mittelwald mehr Großhorste zu finden, die wertvoll für Seeadler und Kaiseradler, sowie den Schwarzstorch sind. Darüber hinaus bevorzugen Greifvögel strukturierte Altholzbestände mit einer ausgeprägten vertikalen Schichtung und einem hohen Totholzanteil. Diese Strukturen deuten auf einen geringen forstlichen Nutzen und dadurch eine geringe menschliche Störung der Nistplätze hin. Die genannten Kriterien erfüllen insbesondere eingerichtete Horstschutzgebiete, die frei von forstlicher Nutzung sind. Die Ausdehnung der Altholzbestände, die Reduzierung von Störungen durch den Menschen sowie die Dynamisierung der Au durch Revitalisierungsprojekte sind wichtige Schritte für einen langfristigen Erhalt der vielfältigen Greifvogelfauna der March-Auen.Between Austria, Slovakia and the Czech Republic, were studied in 2008. The study area (19.7 km2) had not been explored by ornithologists until the 1990s due to the considerable flood dynamics and the subsequent limited accessibility. The present field study was performed between January and July 2008 between Hohenau and Drösing (Lower Austria), consisting of two reference areas of comparable size but with different cultivation techniques, i.e. the high forest cultivation in the North (960 ha) and the middle forest cultivation in the South (1010 ha). Additionally, the field study was conducted to explore the influence of the vegetation structure around the nesting site (microhabitat, r=15 m, 706.5 m2) and the landscape characteristics (macrohabitat, r=250 m, 19.6 ha) on the habitat choices of birds of prey. To get a representative sample for comparison, the same data were collected at 50 randomly selected sites. Aeries were mapped along transects between 50 m intervals, and 167 were found in total. 57 out of 167 aeries were occupied by birds of prey. In total, nine breeding raptor species were recorded. The most abundant species was the Common Buzzard (Buteo buteo), occupying 34 aeries, followed by the Marsh Harrier (Circus aeroginosus) with five or six pairs. The Red Kite (Milvus milvus) population, with a quantity of three pairs was remarkable on a national scale. The Black Kite (Milvus migrans) (three pairs), the Honey Buzzard (Pernis apivorus) (three pairs), the Goshawk (Accipiter gentilis) (three pairs), the Kestrel (Falco tinnunculus) (two pairs) and the Hobby (Falco subbuteo) (two pairs) also bred in the study area. Since 2002 the White-tailed Eagle (Haliaeetus albicilla) has bred successfully in the floodplains. The Sparrowhawk (Accipiter nisus), the Saker Falcon (Falco cherrug) and the Imperial Eagle (Aquila heliaca) were not found as breeders in the study area, but were known to breed nearby. The results indicated a population growth of the Common Buzzard, whereas the density of other predatory birds has been steady for the last 15 years. The density is high compared to other places in central Europe, including the Danube floodplains in Austria. Besides, the density seems to be independent from the type of cultivation. The data concerning the habitat structure were analyzed in a Geographic Information System (GIS) and indicate the March flood-plain forests as very attractive for raptors. The investigation area offers a varied and structured landscape with abundant waterbodies and meadows. Predatory birds prefer old growth trees, particularly oaks (Quercus sp.) and poplars (Populus sp.) for nesting. These types of trees are numerous in middle forest cultivation. Additionally, a higher number of older aeries can be found there compared to high forest cultivations. Birds of prey prefer a distinctive forest structure with plenty of deadwood, far away from paths or protected by dense shrub and undergrowth. Therefore, the conservation of mature forests, the reduction of human disturbance and the reactivation of the flood dynamics could have a positive effect on the raptor population in the long term

Pollen Processing Behavior of Heliconius Butterflies: A Derived Grooming Behavior

Pollen feeding behaviors Heliconius and Laparus (Lepidoptera: Nymphalidae) represent a key innovation that has shaped other life history traits of these neotropical butterflies. Although all flower visiting Lepidoptera regularly come in contact with pollen, only Heliconius and Laparus butterflies actively collect pollen with the proboscis and subsequently take up nutrients from the pollen grains. This study focused on the behavior of pollen processing and compared the movement patterns with proboscis grooming behavior in various nymphalid butterflies using video analysis. The proboscis movements of pollen processing behavior consisted of a lengthy series of repeated coiling and uncoiling movements in a loosely coiled proboscis position combined with up and down movements and the release of saliva. The proboscis-grooming behavior was triggered by contamination of the proboscis in both pollen feeding and non-pollen feeding nymphalid butterflies. Proboscis grooming movements included interrupted series of coiling and uncoiling movements, characteristic sideways movements, proboscis lifting, and occasionally full extension of the proboscis. Discharge of saliva was more pronounced in pollen feeding species than in non-pollen feeding butterfly species. We conclude that the pollen processing behavior of Heliconius and Laparus is a modified proboscis grooming behavior that originally served to clean the proboscis after contamination with particles

Experimental GHZ Entanglement beyond Qubits

The Greenberger-Horne-Zeilinger (GHZ) argument provides an all-or-nothing contradiction between quantum mechanics and local-realistic theories. In its original formulation, GHZ investigated three and four particles entangled in two dimensions only. Very recently, higher dimensional contradictions especially in three dimensions and three particles have been discovered but it has remained unclear how to produce such states. In this article we experimentally show how to generate a three-dimensional GHZ state from two-photon orbital-angular-momentum entanglement. The first suggestion for a setup which generates three-dimensional GHZ entanglement from these entangled pairs came from using the computer algorithm Melvin. The procedure employs novel concepts significantly beyond the qubit case. Our experiment opens up the possibility of a truly high-dimensional test of the GHZ-contradiction which, interestingly, employs non-Hermitian operators.Comment: 6+6 pages, 8 figure

Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure

Although anthophilous Coleoptera are regarded to be unspecialised flower-visiting insects, monkey beetles (Scarabaeidae: Hopliini) represent one of the most important groups of pollinating insects in South Africa’s floristic hotspot of the Greater Cape Region. South African monkey beetles are known to feed on floral tissue; however, some species seem to specialise on pollen and/or nectar. The present study examined the mouthpart morphology and gut content of various hopliine species to draw conclusions on their feeding preferences. According to the specialisations of their mouthparts, the investigated species were classified into different feeding groups. Adaptations to pollen-feeding included a well-developed, toothed molar and a lobe-like, setose lacinia mobilis on the mandible as well as curled hairs or sclerotized teeth on the galea of the maxillae. Furthermore, elongated mouthparts were interpreted as adaptations for nectar feeding. Floral- and folial-tissue feeding species showed sclerotized teeth on the maxilla, but the lacinia was mostly found to be reduced to a sclerotized ledge. While species could clearly be identified as floral or folial tissue feeding, several species showed intermediate traits suggesting both pollen and nectar feeding adaptations. Mismatches found between mouthpart morphology and previously reported flower visiting behaviours across different genera and species requires alternative explanations, not necessarily associated with feeding preferences. Although detailed examinations of the mouthparts allowed conclusions about the feeding preference and flower-visiting behaviour, additional morphological and behavioural investigations, combined with greater taxon sampling and phylogenetic data, are still necessary to fully understand hopliine host plant relationships, related to monkey beetle diversity

Effect of anisotropy and destructuration on behavior of Haarajoki test embankment

This paper investigates the influence of anisotropy and destructuration on the behavior of Haarajoki test embankment, which was built by the Finnish National Road Administration as a noise barrier in 1997 on a soft clay deposit. Half of the embankment is constructed on an area improved with prefabricated vertical drains, while the other half is constructed on the natural deposit without any ground improvement. The construction and consolidation of the embankment is analyzed with the finite-element method using three different constitutive models to represent the soft clay. Two recently proposed constitutive models, namely S-CLAY1 which accounts for initial and plastic strain induced anisotropy, and its extension, called S-CLAY1S which accounts, additionally, for interparticle bonding and degradation of bonds, were used in the analysis. For comparison, the problem is also analyzed with the isotropic modified cam clay model. The results of the numerical analyses are compared with the field measurements. The simulations reveal the influence that anisotropy and destructuration have on the behavior of an embankment on soft clay

Momentum transfer for momentum transfer-free which-path experiments

We analyze the origin of interference disappearance in which-path double aperture experiments. We show that we can unambiguously define an observable momentum transfer between the quantum particle and the path detector and we prove in particular that the so called ``momentum transfer free'' experiments can be in fact logically interpreted in term of momentum transfer.Comment: to appear in Phys. Rev . A (2006). (7 pages, 2 figures