Metallurgical Design and Development of NASA Crawler/Transporter Tread Belt Shoe Castings

The NASA Crawler/Transporters (CT-1 and CT-2) used to transport the Space Shuffles are one of the largest tracked vehicles in existence today. Two of these machines have been used to move space flight vehicles at Kennedy Space Center since the Apollo missions of the 1960's and relatively few modifications have been made to keep them operational. In September of 2003 during normal Crawler/Transporter operations cracks were observed along the roller pad surfaces of several tread belt shoes. Further examination showed 20 cracked shoes on CT-1 and 40 cracked shoes on CT-2 and a formal failure analysis investigation was undertaken while the cracked shoes were replaced. Six shoes were cross-sectioned with the fracture surfaces exposed and it was determined that the cracks were due to fatigue that initiated on the internal casting web channels at pre-existing casting defects and propagated through thickness both transgranularly and intergranularly between internal shrinkage cavities, porosity, and along austenitic and ferritic grain boundaries. The original shoes were cast during the 1960's using a modified 861330 steel with slightly higher levels of chromium, nickel and molybdenum followed by heat treatment to achieve a minimum tensile strength of 11 Oksi. Subsequent metallurgical analysis of the tread belt shoes after multiple failures showed excessive internal defects, alloy segregation, a nonuniform ferritic/ bainitic/martensitic microstructure, and low average tensile properties indicative of poor casting and poor heat-treatment. As a result, NASA funded an initiative to replace all of the tread belt shoes on both crawler/transporters along with a redesign of the alloy, manufacturing, and heat-treatment to create a homogeneous cast structure with uniform mechanical and metallurgical properties. ME Global, a wholly owned subsidiary of ME Elecmetal based in Minneapolis, MN was selected as manufacturing and design partner to develop the new shoes and this paper describes the research, development, and manufacturing that resulted in the successful delivery of 1044 new Crawler/Transporter tread belt shoes all meeting rigid metallurgical and mechanical design criteria derived from finite element modeling of the stress loads required for safe space shuttle transport

Composite powder particles

A liquid coating composition including a coating vehicle and composite powder particles disposed within the coating vehicle. Each composite powder particle may include a magnesium component, a zinc component, and an indium component

Bulk Handling of Milk on Texas Dairy Farms.

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Sex-specific predictors of improved walking with step-monitored, home-based exercise in peripheral artery disease

The aim of this study was to determine whether baseline clinical characteristics and the duration and intensity of ambulation during our step-monitored home-based exercise program were predictive of changes in ambulatory outcomes at completion of the program in symptomatic patients with peripheral artery disease (PAD). Twenty-two men (ankle–brachial index (ABI) = 0.71 ± 0.19) and 24 women (ABI = 0.66 ± 0.23) completed the home exercise program, consisting of intermittent walking to mild-to-moderate claudication pain for 3 months. Ambulatory outcome measures were peak walking time (PWT) and claudication onset time (COT) during a treadmill test, and the distance recorded during a 6-minute walk distance test (6MWD). Men experienced significant increases (p<0.01) in COT, PWT, and 6MWD following the home exercise program, and women had significant increases in 6MWD (p<0.01) and PWT (p<0.05). In women, average exercise cadence during the home exercise sessions was the only predictor that entered the model for change in COT (p=0.082), and was the first predictor in the model for change in PWT (p=0.029) and 6MWD (p=0.006). In men, the ABI was the only predictor that entered the model for change in 6MWD (p=0.002), and ABI was a predictor along with metabolic syndrome in the model for change in COT (p=0.003). No variables entered the model for change in PWT. Faster ambulatory cadence during the step-monitored home-based exercise program may predict greater improvements in ambulatory function in women, whereas having less severe PAD and comorbid burden at baseline may predict greater improvements in ambulatory function in men. ClinicalTrials.gov Identifier: NCT00618670Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Sensory and instrumental analysis of medium and long shelf-life Charentais cantaloupe melons (Cucumis melo L.) harvested at different maturities

The flavour profiles of two genotypes of Charentais cantaloupe melons (medium shelf-life and long shelf-life), harvested at two distinct maturities (immature and mature fruit), were investigated. Dynamic headspace extraction (DHE), solid-phase extraction (SPE), gas chromatography–mass spectrometry (GC-MS) and gas chromatography–olfactometry/mass spectrometry (GC-O/MS) were used to determine volatile and semi-volatile compounds. Qualitative descriptive analysis (QDA) was used to assess the organoleptic impact of the different melons and the sensory data were correlated with the chemical analysis. There were significant, consistent and substantial differences between the mature and immature fruit for the medium shelf-life genotype, the less mature giving a green, cucumber character and lacking the sweet, fruity character of the mature fruit. However, maturity at harvest had a much smaller impact on the long shelf-life melons and fewer differences were detected. These long shelf-life melons tasted sweet, but lacked fruity flavours, instead exhibiting a musty, earthy character

Spray timing to control Botrytis fruit rot and tarnished plant bug in day-neutral strawberries, 1991I

The trial was held at the Iowa State University Horticulture Farm in 1991. Day-neutral strawberries planted in May 1991 on sand loam (fine, loamy, mixed mesic, Typic Halpudoll) soil were arranged in a randomized complete block design with five replications and 3 treatments. Each block was a 100-ft-long double row of plants with 12-in. spacing between plants, and treatment subplots within blocks were 20-ft segments of the double row. Data were taken only from the center 15 ft of each subplot. Timing of fungicide sprays for Botrytis fruit rot in the model-driven treatment was based on a leaf wetness-temperature model proposed by M. Ellis (pers. comm., Department of Plant Pathology, OARDC, Wooster, Ohio and Bulger et al, Phytopathology 77:1225-1230). Timing of insecticide sprays for tarnished plant bug in the modeldriven treatment was based on published criteria (Kovach et al. 1990. Strawberry Scouting Procedures. Bulletin No . 203, New York State IPM Program. p. 18). In the weekly treatment, insecticides and fungicides were applied at 7-day inter-vals. No pesticide sprays were applied in either treatment until blooms appeared (5 Jul). Fungicides used (rates per 100 gal) were Ronilan FL (0.5 pt) or Rovral 50 WP (8 oz), tank-mixed with Captan 50 WP (2 lb). The insecticide used was Sevin 50 WP (2 lb). Pesticides were applied to runoff, using a Solo backpack sprayer (Model No. 425) with a flat-fan nozzle at approximately 30 psi pressure. Leaf wetness and temperature were measured in an apple orchard 0.3 mi from the strawberry plot, using a CR-10 micrologger and appropriate sensors (Campbell Scientific, Logan, UT). Tar-nished plant bug (TPB) populations were monitored weekly by tapping 10 fruit clusters per subplot into a white plastic dish and counting the number of TPB nymphs. The action threshold for insecticide spraying in the modeldriven treatment was a mean count of 0.5 nymphs/cluster. Ripe fruit were picked by hand, counted, and weighed one to three times/wk. At each picking, damaged berries were classed by the probable source of damage, and these classes were counted and weighed

Bulk Handling of Milk on Texas Dairy Farms.

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Costs, Savings and Financing Bulk Tanks on Texas Dairy Farms.

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Diversity of Lecidea (Lecideaceae, Ascomycota) species revealed by molecular data and morphological characters

The diversity of lichens, especially crustose species, in continental Antarctica is still poorly known. To overcome difficulties with the morphology based species delimitations in these groups, we employed molecular data (nuclear ITS and mitochondrial SSU rDNA sequences) to test species boundaries within the genus Lecidea. Sampling was done along a north–south transect at five different areas in the Ross Sea region (Cape Hallett, Botany Bay to Mount Suess, Taylor Valley, Darwin Area and Mount Kyffin). A total of 153 specimens were collected from 13 localities. Phylogenetic analyses also include specimens from other regions in Antarctica and non-Antarctic areas. Maximum parsimony, maximum likelihood and Bayesian analyses agreed in placing the samples from continental Antarctica into four major groups. Based on this phylogenetic estimate, we restudied the micromorphology and secondary chemistry of these four clades to evaluate the use of these characters as phylogenetic discriminators. These clades are identified as the following species Lecidea cancriformis, L. andersonii as well as the new species L. polypycnidophora Ruprecht & Türk sp. nov. and another previously unnamed clade of uncertain status, referred to as Lecidea sp. (L. UCR1)

Kinetic modelling of acrylamide formation during the finish-frying of french fries with variable maltose content

In light of a recent update in EU regulations governing levels of acrylamide in foodstuffs, further understanding of the role of different precursors is fundamental to extending mitigation strategies into a wider product range. Kinetic modelling was used to investigate the role of maltose in the formation of acrylamide during the finish-frying of french fries. The maltose concentration of raw white potato strips was systematically increased to observe the effect of this reducing disaccharide on acrylamide formation. A mathematical model, incorporating glucose, fructose and maltose and based on known Maillard reaction pathways, was developed which showed that acrylamide formation from maltose only contributed <10% to the total acrylamide. An additional kinetic model allowed for the formation of acrylamide directly from sugar-asparagine glycoconjugates. This model suggested that under these conditions, it is unlikely that acrylamide is formed directly from the maltose-asparagine conjugate