Power system phase rotation and polarized protective relays

Many common protective relays used in protection of power equipment are sensitive to phase sequence rotation of the utility supply. A method of analyzing the relay response to the respective phase rotation and other possible variables is described. It is demonstrated that phase rotation usually does not affect zero-sequence polarized relays. The technique is an exercise in voltage and current phasors, maximum torque lines of polarized relays, and the possible effect of system power factor. The following relays are discussed: directional power relay (IEEE Protective Device No.32) as used to protect prime movers on induction and synchronous generators from being motored by the generator due to loss of mechanical power; directional VAr relay (IEEE Protective Device No.55) as used to protect synchronous motors and synchronous generators from receiving VArs from the external power system due to loss of field excitation; directional current phase relay (IEEE Protective Device No.67) as used to detect reverse current flow into a power system from another source due to a system phase fault; and directional current ground relay (IEEE Protective Device No.67N) as used to detect reverse ground current flow into a power system from another source due to a system ground fault     

Polar and Neutral Lipid Composition in the Pelagic Tunicate <Emphasis Type="Italic">Pyrosoma atlanticum</Emphasis>

Structure and functioning of colonial pyrosomes are largely undescribed and their lipid characteristics have received limited attention. The aim of this paper is to fill this gap on one of the dominant species Pyrosoma atlanticum. Lipid content is tightly coupled to size and weight. Lipid composition shows a large dominance of structural polar lipids. Neutral lipids were dominated by sterols with low levels of acylglycerols and free fatty acids. Phospholipids show a dominance of PC with intermediate percentages of PE and DPG. Other constituents (PS, PI, LPC, sphingolipids) were present at lower levels. Fatty acid composition of DAG and TAG showed a dominance of saturated acids (16:0, 14:0), DHA and intermediate levels of MUFA. Phospholipids were dominated by DHA with values exceeding 30% of total FA in all categories except for PI, where lower percentages occurred. Saturated acids were second in abundance with MUFA showing intermediate concentrations. Sterols were dominated by 24-methylcholesta-5,22E-dien-3beta-ol with more than 22% of the total sterol. Cholesterol (cholest-5-en-3beta-ol) represented only 12 % of the total while 24-methylcholesta-5,24(28)E-dien-3beta-ol accounted for 11% of the total sterols. The low levels of triacylglycerols and free fatty acids, coupled with high concentrations of glycolipids and phytoplankton-derived degraded chloropigments, is evidence of a direct link with the digestive activity and substantiate the idea of a high physiological turnover as an alternative to large lipid accumulation. The fatty acid and sterol profiles are consistent with a diverse phytoplankton diet, and a strong contribution of phospholipid classes to energy needs, including locomotion.     

A hybrid ray-wave optics model to study the scattering behavior of silver metallic paint systems

The gonioapparent lightness of a metallic paint system depends strongly on the 3D microstructure of the platelet-containing basecoat layer, and on the platelet roughness. Current optical models which are used to simulate the paint’s appearance, however, ignore the multi-scale and multi-dimensional microstructural features, which limits their predictive power. Here, we describe a hybrid, ray-wave optics model for metallic paints. This model incorporates the ray-optics of the 3D platelet microstructure and the wave effects that result from the surface roughness of the platelets. This model is used to link the roughness to the reflection lobes of the aluminum platelets, and to the gonioapparent lightness of the paint system. Predicted lightness values from our model matched, at most viewing angles, measurements from physical paint samples. This model can be used to explore the effect of platelet surface roughness on the lightness of the complete paint system and predict the appearance of paints with different platelet microstructures.     

Lipids and buoyancy in Southern Ocean pteropods

The lipids of Clione limacina, a Southern Ocean pteropod (order Gymnosomata), contain 28% diacylglyceryl ether (DAGE) (as percentage of total lipid) whereas the pteropod Limacina helicina (order Thecosomata) lacks DAGE. The alkyl glyceryl ether diols (1-O-alkyl glycerols, GE) of Clione DAGE are dominated by 16∶0 (60%) and 15∶0 (21%), in contrast with deep-sea shark liver DAGE, which is dominated by 18∶1 GE. The fatty acid profiles of Clione and Limacina are similar (28–32% polyunsaturated, 26–34% monounsaturated) as are the sterols, which include 24-methylenecholesterol, transdehydrocholesterol, cholesterol, and desmosterol. This finding probably reflects the fact that Limacina is the major food source for Clione. Spongiobranchaea australis, another Southern Ocean pteropod (order Gymnosomata), has 0.9–1.7% DAGE, but has less lipid (3.3–4.8 mg/g lipid, wet weight) than Clione (50.8 mg/g lipid, wet weight). We propose a buoyancy role for DAGE in Clione since Limacina has bubbles for flotation which Clione lack; DAGE provides 23% more uplift than triacylglycerol at a concentration of 1.025 g/mL seawater.     

Numerical Modeling of a Post & Dome Snap-Fit Feature

Snap-fits are often designed using guides that rely on classic beam theory, with the basic assumption that the beam undergoes small rotations and displacements. This is a poor assumption, for they typically experience both large rotations and displacements due to loading offset from the neutral axis and axial loading. This paper investigates the performance of the post & dome feature, establishes its nomenclature, and derives the equations needed to intelligently design different variations of it. The post & dome feature was selected for analysis because it is a high performance snap-fit that is self-datuming and can withstand some shear loading in addition to retention. The design equations were generated in three steps. First, an experimental array was created using a design of experiments approach. Finite element methods and multiple regression techniques were used in lieu of beam equations models for each of the trials in the experimental array. Finally, response surface methods were used to develop response curves based on the performance data generated by the finite element models. Sensitivity data was plotted for both the main effects and selected variable interactions. The traditional benchmarks for defining high performance snap-fits are retention strength, insertion force, and insertion strain. This paper uses an expanded definition of these benchmarks that also includes locking ratio (the ratio of retention force to insertion force).     

Effects of punishment on response latency in extraverts.

Previous findings indicate that in comparison to introverts, extraverts are prone to form responses that are resistant to interruption by punishment. Because the tendency to stop and reflect following punishment may be crucial for subsequent learning, the present study examined differences between introverts' and extraverts' reactions to punishment using response latency on the trial following punishment as the dependent variable. 66 extraverted and 66 introverted male undergraduates, selected on the basis of Eysenck Personality Questionnaire scores, performed a pattern-matching task in which they received noncontingent 50% success and 50% failure feedback under 3 incentive conditions: reward only, punishment only, or both. As predicted, a significant interaction was found in the both incentive condition, reflecting the tendency of extraverts to respond more quickly and introverts more slowly following punishment than reward. No significant effects were found in the other 2 conditions, although extraverts tended to respond more quickly overall when only reward was given. A 2nd experiment, with 101 male undergraduates, that used reward-only and punishment-only feedback replicated this finding and yielded a significant group?×?condition interaction. Results indicate that in contrast to introverts, extraverts are activated by the availability of reward and, paradoxically, that punishment may facilitate rather than interrupt extraverts' reward-seeking behavior. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Data Link for Agricultural and Off-Highway Communications

There is a growing need for data communications in the agricultural and off-highway vehicle industry. An industry-wide search has revealed that there is no standard protocol currently in existence that adequately meets all identified requirements. This paper presents a data communication protocol which was developed to meet the needs of agricultural and off-highway equipment manufacturers.     

Analog and digital circuits using organic thin-film transistors onpolyester substrates

We have fabricated and characterized analog and digital circuits using organic thin-film transistors on polyester film substrates. These are the first reported dynamic results for organic circuits fabricated on polyester substrates. The high-performance pentacene transistors yield circuits with the highest reported clock frequencies for organic circuits