X-ray based extensometry

A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology

Longwall shearer tracking system

A tracking system for measuring and recording the movements of a longwall shearer vehicle includes an optical tracking assembly carried at one end of a desired vehicle path and a retroreflector assembly carried by the vehicle. Continuous horizontal and vertical light beams are alternately transmitted by means of a rotating Dove prism to the reflector assembly. A vertically reciprocating reflector interrupts the continuous light beams and converts these to discrete horizontal and vertical light beam images transmitted at spaced intervals along the path. A second rotating Dove prism rotates the vertical images to convert them to a second series of horizontal images while the first mentioned horizontal images are left unrotated and horizontal. The images are recorded on a film

Reaching Approximate Byzantine Consensus with Multi-hop Communication

We address the problem of reaching consensus in the presence of Byzantine faults. In particular, we are interested in investigating the impact of messages relay on the network connectivity for a correct iterative approximate Byzantine consensus algorithm to exist. The network is modeled by a simple directed graph. We assume a node can send messages to another node that is up to $l$ hops away via forwarding by the intermediate nodes on the routes, where $l\in \mathbb{N}$ is a natural number. We characterize the necessary and sufficient topological conditions on the network structure. The tight conditions we found are consistent with the tight conditions identified for $l=1$, where only local communication is allowed, and are strictly weaker for $l>1$. Let $l^*$ denote the length of a longest path in the given network. For $l\ge l^*$ and undirected graphs, our conditions hold if and only if $n\ge 3f+1$ and the node-connectivity of the given graph is at least $2f+1$ , where $n$ is the total number of nodes and $f$ is the maximal number of Byzantine nodes; and for $l\ge l^*$ and directed graphs, our conditions is equivalent to the tight condition found for exact Byzantine consensus. Our sufficiency is shown by constructing a correct algorithm, wherein the trim function is constructed based on investigating a newly introduced minimal messages cover property. The trim function proposed also works over multi-graphs.Comment: 24 pages, 1 figure. arXiv admin note: text overlap with arXiv:1203.188

The Brimfield (?) and Paxton (?) Formations in Northeastern Connecticut

Guidebook for field trips in Connecticut: New England Intercollegiate Geological Conference 60th annual meeting, Yale University, New Haven, Connecticut, October 25-27, 1968: Trip F-

TECHNIQUE CHARACTERISTICS OF ELITE BREASTSTROKE SWIMMERS

INTRODUCTION-There have been substantial changes in technique in breaststroke swimming following the introduction of the 'wave-action' technique. Due to continual experimentation by swimmers and coaches to find the technique that best suits each swimmer, the observable characteristics of elite swimmers vary considerably. The purpose of this study was to investigate the technique characteristics of elite breaststroke swimmers to identify and quantify aspects of technique that are common among elite swimmers and those which are variable. METHODS-Two above water and two below water cameras were used to obtain three-dimensional data from eight internationally elite breaststroke swimmers swimming in the 100m and 200m heats and finals of the 1992 Olympics in Barcelona. The swimmers were recorded while they passed between five and ten metres fram the turning end of the pool. The time histories of angles describing the orientation of the swimmer were determined using Peak Performance Technologies three-dimensional digitising and analysis software. The amplitude and frequency of waveforms comprising the vertical undulations of the body parts and the phase relationships between them were determined by Fourier analysis RESULTS-There was considerable variability among swimmers in the time histories of angular motions and in the amplitudes and phase relationships of the waveforms comprising the vertical undulations. In the case of all swimmers the vertical undulations of the vertex of the head and shoulders resembled simple sinusoidal waveforms with a frequency equivalent to that of the stroke cycle. The vertical undulations of the hips, knees, and ankles displayed large contributions by hlgher frequency components. The realtive magnitudes of these contributions varied considerably among swimmers. CONCLUSION-It was concluded that breaststroke swimmers use different techniques to achieve top performance

AN INTRODUCTION TO VIRGINIA ISSUES: INFORMATION AND ANALYSIS: SPECIAL REPORT FOR VIRGINIA COOPERATIVE EXTENSION

Community/Rural/Urban Development, Labor and Human Capital, Land Economics/Use,

Lessons Learned from Liquefaction and Lifeline Performance During San Francisco Earthquakes

This paper presents information about subsurface conditions, liquefaction-induced ground movements, and lifeline performance during the 1906 and 1989 earthquakes in San Francisco. Three sites of soil liquefaction and pipeline damage during both earthquakes are evaluated, including the Marina, South of Market, and Mission Creek areas. Important lessons are summarized about the effects of transient lateral shear strains on pipeline performance, post liquefaction consolidation, use of submerged fill thickness as a microzonation technique for predicting liquefaction severity and potential pipeline damage, the relationship between surface manifestations of liquefaction and subsurface geometry of deposits, and factors affecting the magnitude of lateral spread

Validation of Body Volume Acquisition by Using Elliptical Zone Method

The elliptical zone method (E-Zone) can be used to obtain reliable body volume data including total body volume and segmental volumes with inexpensive and portable equipment. The purpose of this research was to assess the accuracy of body volume data obtained from E-Zone by comparing them with those acquired from the 3D photonic scanning method (3DPS). 17 male participants with diverse somatotypes were recruited. Each participant was scanned twice on the same day by a 3D whole-body scanner and photographed twice for the E-Zone analysis. The body volume data acquired from 3DPS was regarded as the reference against which the accuracy of the E-Zone was assessed. The relative technical error of measurement (TEM) of total body volume estimations was around 3% for E-Zone. E-Zone can estimate the segmental volumes of upper torso, lower torso, thigh, shank, upper arm and lower arm accurately (relative TEM<10%) but the accuracy for small segments including the neck, hand and foot were poor. In summary, E-Zone provides a reliable, inexpensive, portable, and simple method to obtain reasonable estimates of total body volume and to indicate segmental volume distribution