11,002 research outputs found
Photomechanical Investigation of Structural Behavior of Gyroscope Components. Task IV - Analysis of Initial Redesign of AB5-K8 GYROSCOPE
Photomechanics of structure and materials in redesigned AB5-K8 gyroscope component
Soliton effects in dangling-bond wires on Si(001)
Dangling bond wires on Si(001) are prototypical one dimensional wires, which
are expected to show polaronic and solitonic effects. We present electronic
structure calculations, using the tight binding model, of solitons in
dangling-bond wires, and demonstrate that these defects are stable in
even-length wires, although approximately 0.1 eV higher in energy than a
perfect wire. We also note that in contrast to conjugated polymer systems,
there are two types of soliton and that the type of soliton has strong effects
on the energetics of the bandgap edges, with formation of intra-gap states
between 0.1 eV and 0.2 eV from the band edges. These intra-gap states are
localised on the atoms comprising the soliton.Comment: 6 pages, 3 figures, 3 tables, submitted to Phys. Rev.
The evolution of pebble size and shape in space and time
We propose a mathematical model which suggests that the two main geological
observations about shingle beaches, i.e. the emergence of predominant pebble
size ratios and strong segregation by size are interrelated. Our model is a
based on a system of ODEs called the box equations, describing the evolution of
pebble ratios. We derive these ODEs as a heuristic approximation of Bloore's
PDE describing collisional abrasion. While representing a radical
simplification of the latter, our system admits the inclusion of additional
terms related to frictional abrasion. We show that nontrivial attractors
(corresponding to predominant pebble size ratios) only exist in the presence of
friction. By interpreting our equations as a Markov process, we illustrate by
direct simulation that these attractors may only stabilized by the ongoing
segregation process.Comment: 22 pages, 8 figure
TB89: Motor and Elective Activity of the Duodenum of Broilers
Recordings of pressure changes and electrical activity from the proximal small intestine of seven to eight-week-old unanesthetized chickens were made with chronically implanted transducers. The recordings were used to quantitate and determine the relationships among basic electric rhythm (BER), spike potentials (SP), and intestinal contractions (IC) of the duodenum. The omnipresence of the BER was demonstrated. SP were recorded whenever IC were detected. SP numbers and amplitudes were directly related to the strength of IC. Acetylcholine caused a general increase in the number and amplitude of both SP and IC. Epinephrine completely abolished both SP and IC. The results suggest that BER may represent the stimulus that initiates SP, and therefore, IC of the duodenum.https://digitalcommons.library.umaine.edu/aes_techbulletin/1096/thumbnail.jp
Tests for cream sediment
Commercial milk plants have employed the sediment test for milk for many years. In fact, the milk sediment test has its place on the milk score card. The amount of sediment is always determined in scoring milk. The test is extremely simple; it consists of passing 1 pint of milk through a sediment tester and catching the sediment present in the milk on a circular pad 1 inch in diameter.
The application of a sediment test to cream, on the other hand, has been attempted only very recently. A test as simple as that for milk is impossible. The cream’s high fat content necessitates warming it to melt the fat so that the sample will filter easily; the variable acidity of cream for butter-making necessitates the use of a neutralizing agent, in many instances in order that the filter pad will not clog. Because of the high fat content of the cream it is imperative to use less than a pint in order to reduce the cost and eliminate the handling of a bulky sample after dilution
An introduction to the EULAR–OMERACT rheumatoid arthritis MRI reference image atlas
This article gives a short overview of the development and characteristics of the OMERACT rheumatoid arthritis MRI scoring system (RAMRIS), followed by an introduction to the use of the EULAR–OMERACT rheumatoid arthritis MRI reference image atlas. With this atlas, MRIs of wrist and metacarpophalangeal joints of patients with rheumatoid arthritis can be scored for synovitis, bone oedema, and bone erosion, guided by standard reference images
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