Rings and spirals in barred galaxies. I Building blocks

In this paper we present building blocks which can explain the formation and properties both of spirals and of inner and outer rings in barred galaxies. We first briefly summarise the main results of the full theoretical description we have given elsewhere, presenting them in a more physical way, aimed to an understanding without the requirement of extended knowledge of dynamical systems or of orbital structure. We introduce in this manner the notion of manifolds, which can be thought of as tubes guiding the orbits. The dynamics of these manifolds can govern the properties of spirals and of inner and outer rings in barred galaxies. We find that the bar strength affects how unstable the L1 and L2 Lagrangian points are, the motion within the 5A5A5Amanifold tubes and the time necessary for particles in a manifold to make a complete turn around the galactic centre. We also show that the strength of the bar, or, to be more precise, of the non-axisymmetric forcing at and somewhat beyond the corotation region, determines the resulting morphology. Thus, less strong bars give rise to R1 rings or pseudorings, while stronger bars drive R2, R1R2 and spiral morphologies. We examine the morphology as a function of the main parameters of the bar and present descriptive two dimensional plots to that avail. We also derive how the manifold morphologies and properties are modified if the L1 and L2 Lagrangian points become stable. Finally, we discuss how dissipation affects the manifold properties and compare the manifolds in gas-like and in stellar cases. Comparison with observations, as well as clear predictions to be tested by observations will be given in an accompanying paper.Comment: Typos corrected to match the version in press in MNRA

Thermal design of the space shuttle external tank

The shuttle external tank thermal design presents many challenges in meeting the stringent requirements established by the structures, main propulsion systems, and Orbiter elements. The selected thermal protection design had to meet these requirements, and ease of application, suitability for mass production considering low weight, cost, and high reliability. This development led to a spray-on-foam (SOFI) which covers the entire tank. The need and design for a SOFI material with a dual role of cryogenic insulation and ablator, and the development of the SOFI over SLA concept for high heating areas are discussed. Further issuses of minimum surface ice/frost, no debris, and the development of the TPS spray process considering the required quality and process control are examined

Full-scale aircraft cabin flammability tests of improved fire-resistant materials, test series 2

Full-scale aircraft flammability tests in which the effectiveness of new fire-resistant materials was evaluated by comparing their burning characteristics with those of other fire-resistant aircraft materials were described. New-fire-resistant materials that are more economical and better suited for aircraft use than the previously tested fire-resistant materials were tested. The fuel ignition source for one test was JP-4; a smokeless fuel was used for the other test. Test objectives, methods, materials, and results are presented and discussed. The results indicate that, similar to the fire-resistant materials tested previously, the new materials decompose rather than ignite and do not support fire propagation. Furthermore, the new materials did not produce a flash fire

Development and test of advanced composite components. Center Directors discretionary fund program

This report describes the design, analysis, fabrication, and test of a complex bathtub fitting. Graphite fibers in an epoxy matrix were utilized in manufacturing of 11 components representing four different design and layup concepts. Design allowables were developed for use in the final stress analysis. Strain gage measurements were taken throughout the static load test and correlation of test and analysis data were performed, yielding good understanding of the material behavior and instrumentation requirements for future applications

What LDEF means for development and testing of materials

The Long Duration Exposure Facility (LDEF) served as the ultimate laboratory to provide combined space environmental effects on materials. The LDEF structure and its 57 experiments contained an estimated 12,000 to 14,000 specimens of materials and materials processes. It not only provided information about the resistance of these materials to the space environment but gives us direction into future needs for spacecraft materials development and testing. This paper provides an overview of the materials effects observed on the satellite and suggests recommendations for the future work in space-qualified materials development and space environmental simulation

Proceedings of the 11th Annual Meeting, Southern Soybean Disease Workers (March 27-29, 1984, Ft. Walton Beach, Florida): Economics of Soybean Disease

Contents 1984 Southern Soybean Disease Workers Officers 1984 Southern Soybean Disease Workers Program Committee 1984 Southern Soybean Disease Workers Committee Chairmen Workshop Diagnosing early season soybean disorders. D Stuckey and A Wrather General session Presidential address. HJ Walters Southern United States Soybean Disease Loss Estimate for 1983. Southern Soybean Disease Workers, Soybean Disease Loss Estimate Committee. RP Mulrooney Soybean nematodes. R Dunn presiding A New Publication on the Soybean Cyst Nematode. WF Moore Soybean Cultivars and Development of Populations of Meloidogyne incognita in Soil: A Concept of Tolerance. R Rodríguez-Kábana and DB Weaver A Comparison of Soybean Cultivars for Their Resistance to Meloidogyne incognita and M. arenaria. RA Kinloch Ethylene Dibromide and Alternative Nematicides for Soybeans. RA Dunn Involvement of Fungi in Phytonematode Pathology. G Morgan-Jones and R Rodríguez-Kábana Graduate student presentations. EC McGawley presiding Interaction Between Heterodera glycines and Glomus macrocarpus on Soybeans as Affected by Aldicarb. DP McCormack, DP Schmitt, and KR Barker Phomopsis sp. and Soybean Seedling Emergence: Influence of Soil Water Potential. M Gleason and RS Ferriss Soybean seed, seedling and soil-borne diseases. WS Gazaway presiding Report of Southern Soybean Disease Workers Seed Treatment Committee, 1983. MC McDaniel Effects of Soil Source, Soil Moisture, Seed Quality and Seed Treatment on Soybean Emergence. RE Stuckey, RS Ferriss, and MR Siegel Epidemiological and Mycofloral Relationships in Soybean Seedling Disease. JF Killebrew and KW Roy Seed Treatments for Control of Seedling Diseases and Rhizoctonia Root Rot in No-Till Soybeans. AY Chambers Soybean foliar, pod and stem diseases. JW Shriver presiding Southern Soybean Disease Workers Standardized Foliar Fungicide Test, 1983. AY Chambers and MA Newman Stem Canker in the Southeastern United States. WS Gazaway Timings of Foliar Fungicide Applications on Soybeans in Louisiana. JS Gershey, GT Berggren, and ME Pace Levels of Chlorine in Leaves and Seed Causing Leaf Scorch of Soybeans. MB Parker, TP Gaines, and GJ Gascho Incidence and Yield Loss Estimates on Stem and Foliar Diseases as Affected by Row Spacing and Overhead Irrigation. MC Hirrell and MC McDaniel Foliar Fungicides in Georgia: A Ten-Year Summary. DV Phillips New developments. E Barrett presiding The Use of Microcomputers in Soybean Disease Research. ME Pace, GT Berggren, Jr, and JS Gershey Aerial Web Blight in Mississippi in 1983. JA Fox SSDW Treasurer\u27s repor

It could probably help someone else but not me : a feasibility study of a snack programme offered to meals on wheels clients

Objectives Community-based services, such as Meals on Wheels (MOW), allow older adults to remain in their homes for as long as possible. Many MOW recipients experience decreased appetite that limits intake at mealtimes. This pilot study aimed to determine the feasibility of providing high protein high energy snacks to improve nutrient intakes of MOW clients in a regional centre of New South Wales, Australia. Participants A convenience sample of 12 MOW clients. Intervention Participants received snacks five times a week, in addition to their usual MOW order, for four weeks. Measurements Nutritional status was assessed using the Mini Nutritional Assessment tool. Pre-post changes in dietary intake were assessed using a diet history and food frequency questionnaire. Qualitative interviews conducted in clients’ homes were digitally recorded, transcribed verbatim, and themes identified. Results Post-intervention, there was a trend for an increased energy (mean = +415kJ (SD=1477)/day) and protein (+7.2 (±14.06) g/day) intake. MNA scores significantly increased (P= 0.036) and proportion of respondents categorised as ‘malnourished’ or ‘at risk of malnutrition’ decreased from 17% to 8%, and 67% to 25%, respectively (P Conclusion Provision of an additional daily mid-meal snack may be a useful addition to existing MOW services, for improved energy and protein intakes. However, not all MOW clients at risk of malnutrition perceived the snacks to be beneficial to them

Hybrid Rules with Well-Founded Semantics

A general framework is proposed for integration of rules and external first order theories. It is based on the well-founded semantics of normal logic programs and inspired by ideas of Constraint Logic Programming (CLP) and constructive negation for logic programs. Hybrid rules are normal clauses extended with constraints in the bodies; constraints are certain formulae in the language of the external theory. A hybrid program is a pair of a set of hybrid rules and an external theory. Instances of the framework are obtained by specifying the class of external theories, and the class of constraints. An example instance is integration of (non-disjunctive) Datalog with ontologies formalized as description logics. The paper defines a declarative semantics of hybrid programs and a goal-driven formal operational semantics. The latter can be seen as a generalization of SLS-resolution. It provides a basis for hybrid implementations combining Prolog with constraint solvers. Soundness of the operational semantics is proven. Sufficient conditions for decidability of the declarative semantics, and for completeness of the operational semantics are given