Development of hydrogen resistant alloys

The most hostile operating environments in the O2/H2 Space Shuttle Main Engine are gaseous hydrogen and hydrogen/water vapor. After years of evaluating commercially available alloys, only a few high strength alloys have been found that perform satisfactorily in these environments. This paper describes the evaluation of various compositions of the Fe-Ni-Co system with elemental additions of Cr, Cb, Ti and Al. After processing, notched tensile specimens were tested in 5000 psi hydrogen at room temperature as the prime screening test. The H2/air ratio was used as the selection/rejection criteria

Ontogeny of the Tibial Spur in \u3ci\u3eMegamelus Davisi\u3c/i\u3e (Homoptera: Delphacidae) and its Bearing on Delphacid Classification

The forms of the nymphal tibial spur in Megamelus davisi Van Duzee, and their relation to Muir\u27s classification of delphacid subfamilies and tribes, are discussed

Thin plate buckling mitigation and reduction challenges for naval ships

Thin plate buckling or distortion on ship structures is an ongoing issue for shipbuilders. It has been identified that a significant number of factors can be put in place based on prior knowledge and good practice. Additionally, research work aimed at reducing thin plate distortion has been relatively prolific, particularly in the area of simulation modelling. However, the uptake in the research findings by industry has been relatively low. A number of these findings are discussed and their application considered. For any further reductions in thin plate distortion to be generated there is a clear need for better interaction between the research institutes and the industry

Annotated Records of Species of Pentatomoidea (Hemiptera) Collected at Lights

Records of specimens of Pentatomoidea collected at various light sources in Alabama, Arizona, Florida, Georgia, Illinois, Louisiana, and Texas are presented. Of the 51 species and subspecies reported, about 75% belong to the Pentatomidae

The First Records in Illinois of \u3ci\u3eHeliconius Charitonius\u3c/i\u3e (Lepidoptera: Heliconiidae) and \u3ci\u3ePhoebis Agarithe\u3c/i\u3e (Lepidoptera: Pieridae)

(excerpt) Our key to Illinois butterflies, exclusive of the skippers (Hesperiidae), was published in 1980. It includes those butterflies listed by Irwin and Downey in their 1973 Illinois checklist plus two species,Anaea aidea (Guerin-Meneville) (Nymphalidae) and Celastrina ebenina Clench (Lycaenidae), added to the state list after 1973

A List of the Butterflies (Lepidoptera: Papilionoidea) of the La Rue-Pine Hills Ecological Area

A survey of the adult butterfly fauna of the La Rue-Pine Hills Ecological Area, Union County, Illinois, was conducted from March through July in 1979, and March through November in 1980. Forty nine species and subspecies were collected including all six papilionids known to occur in Illinois. Notes were taken on seasonal flight periods and butterfly-plant associations

Notes on the Biology of \u3ci\u3eNersia Florens\u3c/i\u3e (Homoptera: Fulgoroidea: Dictyopharidae) with Descriptions of Eggs, and First, Second, and Fifth Instars

Information on food plants and laboratory rearing of Nersia florens Stal is provided, and the eggs and Ist, 2nd, and 5th instars are described

Material technology

Advanced high pressure O2/H2 propulsion systems as exemplified by the Space Shuttle Main Engine (SSME) create challenging operating environments for materials. Many components operate in either hydrogen or hydrogen-steam environments which may significantly degrade the performance of common alloys. The objective of the materials technology projects is to develop and evaluate candidate materials for application in advanced high pressure O2/H2 propulsion systems. These new and improved materials are to improve the durability or performance of the SSME or derivative engine. The program includes projects on the following topics: (1) Hydrogen Resistant Alloys; (2) High Pressure O2 Ignition and Burning; (3) Improved Turbine Blades; (4) Improved Turbine Disk Material; (5) Impact Reactivity in High Pressure O2; and Fiber Reinforced Superalloys

Obesity and cancer: existing and new hypotheses for a causal connection

Existing explanations of obesity-associated cancer emphasise direct mutagenic effects of dietary components or hormonal imbalance. Some of these hypotheses are reviewed briefly, but recent evidence suggests a major role for chronic inflammation in cancer risk, possibly involving dietary content. These ideas include the inflammation-induced activation of the kynurenine pathway and its role in feeding and metabolism by activation of the aryl hydrocarbon receptor (AHR) and by modulating synaptic transmission in the brain. Evidence for a role of the kynurenine pathway in carcinogenesis then provides a potentially major link between obesity and cancer. A second new hypothesis is based on evidence that serine proteases can deplete cells of the tumour suppressors Deleted in Colorectal Cancer (DCC) and neogenin. These enzymes include mammalian chymotryptic proteases released by pro-inflammatory neutrophils and macrophages. Blood levels of chymotrypsin itself increase in parallel with food intake. The mechanistically similar bacterial enzyme subtilisin is widespread in the environment, animal probiotics, meat processing and cleaning products. Simple public health schemes in these areas, with selective serine protease inhibitors and AHR antagonists and could prevent a range of intestinal and other cancers

Odonata at a Small Woodland Pond in Southern Illinois

A survey of the adult odonate fauna of a small woodland pond in Pope County, Illinois, was conducted during 1983--·1984. Twenty-four species were collected including Aeshna mutata and Anax longipes. In addition, Libellula vibrans was collected in 1982, and Aeshna sp. (probably u. umbrosa) observed the same year but not collected