Alloying principles and strengthening mechanisms Discussion supplements for committee 5 report

Alloying and strengthening mechanisms for heat resistant refractory metal

Progress in advanced high temperature turbine materials, coatings, and technology

Material categories as well as coatings and recent turbine cooling developments are reviewed. Current state of the art is identified, and as assessment, when appropriate, of progress, problems, and future directions is provided

Progress in advanced high temperature materials technology

Significant progress has recently been made in many high temperature material categories pertinent to such applications by the industrial community. These include metal matrix composites, superalloys, directionally solidified eutectics, coatings, and ceramics. Each of these material categories is reviewed and the current state-of-the-art identified, including some assessment, when appropriate, of progress, problems, and future directions

A 3+1 Decomposition of the Minimal Standard-Model Extension Gravitational Sector

The 3+1 (ADM) formulation of General Relativity is used in, for example, canonical quantum gravity and numerical relativity. Here we present a 3+1 decomposition of the minimal Standard-Model Extension gravity Lagrangian. By choosing the leaves of foliation to lie along a timelike vector field we write the theory in a form which will allow for comparison and matching to other gravity models.Comment: Presented at the Eighth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, May 12-16, 201

Ubiquitous energy storage

This paper presents a vision of a future power system with "ubiquitous energy storage", where storage would be utilized at all levels of the electricity system. The growing requirement for storage is reviewed, driven by the expansion of distributed generation. The capabilities and existing applications of various storage technologies are presented, providing a useful review of the state of the art. Energy storage will have to be integrated with the power system and there are various ways in which this may be achieved. Some of these options are discussed, as are commercial and regulatory issues. In two case studies, the costs and benefits of some storage options are assessed. It is concluded that electrical storage is not cost effective but that thermal storage offers attractive opportunities

NASA Research Bearing on Jet Engine Reliability

Turbojet engine reliability has long been an intense interest to the military users of this type of aircraft propulsion. With the recent inauguration of commercial jet transport this subject has assumed a new dimension of importance. In January l96 the Lewis Research Center of the NASA (then the MACA) published the results of an extensive study on the factors that affect the opera- center dot tional reliability of turbojet engines (ref. 1). At that time the report was classified Confidential. In July l98 this report was declassified. It is thus appropriate at this time to present some of the highlights of the studies described in the NASA report. In no way is it intended to outline the complete contents of the report; rather it is hoped to direct attention to it among those who are center dot directly concerned with this problem. Since the publication of our study over three years ago, the NASA has completed a number of additional investigations that bear significantly on this center dot subject. A second object of this paper, therefore, is to summarize the results of these recent studies and to interpret their significance in relation to turbojet operational reliability

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick layer of hematite gouge with71% ± 1% (1σ) and 18% ± 3% He loss, respectively. Documented He loss requires short-duration, high temperatures during slip. The spatial heterogeneity and enhanced He loss from FM zones are consistent with asperity flash heating (AFH). Asperities \u3e200–300 µm in diameter, producing temperatures \u3e900 °C for ∼1 ms, can explain observed He loss. Results provide new empirical evidence describing AFH and the role of coseismic temperature rise in FM formation. Hematite He thermochronometry can detect AFH and thus seismicity on natural FMs and other thin slip surfaces in the upper seismogenic zone of Earth’s crust