Segregation Ability Research Articles

Stator Inductance Fluctuation of Induction Motor as an Eccentricity Fault Index

A new index is introduced for eccentricity fault diagnosis in three-phase squirrel-cage induction motors. Basically, some physical quantities of the motors structure such as air gap length influence this index, while other operational factors including motor supply, control type, load level, and its fluctuation cannot affect the proposed index. The influence of various eccentricity faults upon this index is investigated and shows the segregation ability of different eccentricity types by the index. It is indicated that the change of load, speed, and saturation level can slightly change the index value. Experimental results confirm the simulation results.

Auditory stream segregation using amplitude modulated vocoder bandpass noise.

We investigated the contribution of amplitude modulation (AM) rate and spectral separation to stream segregation of vocoder bandpass noises. Stimulus sequences were repeated pairs of A and B bursts, where bursts were white noise or vocoder bandpass noise carrying sinusoidal AM (100% modulation depth). Bursts differed either in the center frequency of the noise, or the AM rate, or both. Eight vocoder bands were used. The lowest four bands (1‐2‐3‐4) were combined into one bandpass noise (B bursts) and the higher three bands (3‐4‐5, 4‐5‐6, and 6‐7‐8) were combined to constitute the A bursts. Results show that stream segregation ability increases with greater spectral separation. Larger AM rate separations were associated with stronger segregation abilities, but not when A and B bursts were both white noise. Significant inter‐subject differences were noted. Results suggest that, while both spectral and AM rate separation separations could be cues for auditory stream segregation, stream segregation based on AM rate is more successful when combined with spectral separation. Correlations between segregation ability and understanding of vocoded speech will be discussed.

Auditory stream segregation in children with Asperger syndrome

Individuals with Asperger syndrome (AS) often have difficulties in perceiving speech in noisy environments. The present study investigated whether this might be explained by deficient auditory stream segregation ability, that is, by a more basic difficulty in separating simultaneous sound sources from each other. To this end, auditory event-related brain potentials were recorded from a group of school-aged children with AS and a group of age-matched controls using a paradigm specifically developed for studying stream segregation. Differences in the amplitudes of ERP components were found between groups only in the stream segregation conditions and not for simple feature discrimination. The results indicated that children with AS have difficulties in segregating concurrent sound streams, which ultimately may contribute to the difficulties in speech-in-noise perception.

New features in the dynamics of a ferroin-catalyzed Belousov–Zhabotinsky reaction induced by a zwitterionic surfactant

Interactions between reaction–diffusion systems and aggregated host environments are a subject of widespread interest. In this work, the behavior of the Belousov–Zhabotinsky reaction was investigated in a micellar environment formed by the zwitterionic surfactant N-tetradecyl- N, N-dimethylamine oxide (C 14DMAO). The appearance of an induction period with a threshold-like dependence upon the surfactant concentration, was detected at [C 14DMAO] = 5.0 × 10 −3 mol dm −3. These new features were explained in terms of the segregation ability typical of the amphiphilic self-assembling systems. Numerical simulations were also performed to confirm the proposed mechanism.

Sound segregation based on temporal envelope structure and binaural cues

The ability to segregate two spectrally and temporally overlapping signals based on differences in temporal envelope structure and binaural cues was investigated. Signals were a harmonic tone complex (HTC) with 20 Hz fundamental frequency and a bandpass noise (BPN). Both signals had interaural differences of the same absolute value, but with opposite signs to establish lateralization to different sides of the medial plane, such that their combination yielded two different spatial configurations. As an indication for segregation ability, threshold interaural time and level differences were measured for discrimination between these spatial configurations. Discrimination based on interaural level differences was good, although absolute thresholds depended on signal bandwidth and center frequency. Discrimination based on interaural time differences required the signals' temporal envelope structures to be sufficiently different. Long-term interaural cross-correlation patterns or long-term averaged patterns after equalization-cancellation of the combined signals did not provide information for the discrimination. The binaural system must, therefore, have been capable of processing changes in interaural time differences within the period of the harmonic tone complex, suggesting that monaural information from the temporal envelopes influences the use of binaural information in the perceptual organization of signal components.

Effects and mechanism of Ca on refinement of AZ91D alloy

Ca addition into magnesium alloy is one of the most effective ways to improve high temperature and mechanical properties of magnesium alloys. The influence of calcium on refinement of AZ91D alloy was investigated by optical microscopy, scanning electron microscopy and thermal analysis. It was shown that increasing the amount of added Ca (≤1.0 wt.%Ca), the grain refinement tendency of AZ91D alloy intensified. The related refinement mechanism is as follows: Ca possesses a strong segregation ability in melt alloy and forms an intensive constitutional undercooling in a diffusion layer ahead of the advancing solid/liquid interface which restricts grain growth and promotes nucleation in the melt. The higher the amount of added Ca is, the higher the formation temperature of Al 2Ca phase on grain boundary is, which increases the effect of constitutional undercooling, consequently intensifies the refinement tendency. Besides, with the amount of added Ca increases, the eutectic reaction extent becomes depressed lowered which results in the refinement of eutectic structure.

Preparation of a self-assembled cytochrome c monolayer on a gold substrate for biomolecular device architecture

The segregation ability of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS), a zwitterionic surfactant, on cytochrome c (cyt c) aggregates in a phosphate buffer solution was quantified through the dynamic light-scattering analysis, and CHAPS was found to have an excellent ability in reducing nonspecific affinity among cyt c molecules. When CHAPS was applied to cyt c aggregates on the surface of gold substrates modified with self-assembled cyt c monolayer, the aggregates were found to be successfully eliminated by high-resolution atomic force microscopy image with 30-nm-sized cyt c clusters. This technique is expected to be useful to prepare a self-assembled monolayer of metalloproteins without their aggregates which may degrade the electrochemical property required as a biomolecular electronic device.

Segregation of resin‐bound peptides during solid‐phase synthesis

AbstractTo compare the segregation ability of 1,4‐butanediol dimethacrylate‐crosslinked polystyrene (BDDMA‐PS) and divinylbenzene‐crosslinked polystyrene (DVB‐PS), a set of difficult sequence peptides characterized by high‐arithmetic‐average β‐sheet stabilizing potential (SPβ) and low‐stepwise arithmetic average random coil conformational parameter (Pc*) were synthesized on both supports (∼ 2 mmol Cl g−1) under identical conditions. The yield and purity of the peptides obtained from BDDMS‐PS resin were higher than from DVB‐PS resin. The synthetic efficiency of the new support was found to be its ability to suppress the aggregation of growing peptide chains by β‐sheet formation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1717–1723, 2002

A closed curve is much more than an incomplete one: effect of closure in figure-ground segmentation.

Detection of fragmented closed contours against a cluttered background occurs much beyond the local coherence distance (maximal separation between segments) of nonclosed contours. This implies that the extent of interaction between locally connected detectors is boosted according to the global stimulus structure. We further show that detection of a target probe is facilitated when the probe is positioned inside a closed circle. To explain the striking contour segregation ability found here, and performance enhancement inside closed boundaries, we propose the existence of a synergetic process in early vision.

Developmental analysis of grandchildless (gs(1)N441) mutation in Drosophila melanogaster; abnormal formation of pole cells.

A detailed examination of the developmental features of abnormal formation of pole cells and a functional analysis of the germ plasma of gs(1)N441 embryos were carried out. The germ plasma is morphologically normal. Embryos in which cleavage nuclei show retarded migration to the posterior pole do not form pole cells. Pole cells, following formation, are abnormally segregated and then intermingled between the blastoderm cell layer but retaining normal morphology and differentiating into functional germ cells. The results of cytoplasmic transplantation experiments indicate the autonomous segregation ability of the mutant polar plasma to form pole cells to possibly be affected.