Eye contrast polarity is critical for face recognition by infants

Just as faces share the same basic arrangement of features, with two eyes above a nose above a mouth, human eyes all share the same basic contrast polarity relations, with a sclera lighter than an iris and a pupil, and this is unique among primates. The current study examined whether this bright-dark relationship of sclera to iris plays a critical role in face recognition from early in development. Specifically, we tested face discrimination in 7- and 8-month-old infants while independently manipulating the contrast polarity of the eye region and of the rest of the face. This gave four face contrast polarity conditions: fully positive condition, fully negative condition, positive face with negated eyes ( negative eyes ) condition, and negated face with positive eyes ( positive eyes ) condition. In a familiarization and novelty preference procedure, we found that 7- and 8-month-olds could discriminate between faces only when the contrast polarity of the eyes was preserved (positive) and that this did not depend on the contrast polarity of the rest of the face. This demonstrates the critical role of eye contrast polarity for face recognition in 7- and 8-month-olds and is consistent with previous findings for adults

Effects of Particle Sizes on Sintering Behavior of 316L Stainless Steel Powder

In rapidly evolving powder injection molding technology, the wide prevalence of various microstructures demands the powders of smaller particle sizes. The effects of particle size on the sintering behavior are critical to not only shape retention of microstructure but also its mechanical properties. This study investigates the effects of three different particle sizes on the sintering behavior of the 316L stainless steel (STS316L) samples, prepared by powder injection molding, via the dilatometry experiments. For this purpose, the STS316L powders of three different mean particle sizes, i.e., 2.97, 4.16, and 8.04 mu m, were produced for STS316L. The samples for the dilatometry test were prepared through powder-binder mixing, injection molding, and solvent and thermal debinding. Dilatometry experiments were carried out with the samples in a H-2 atmosphere at three different heating rates of 3, 6, and 10 K/min. The shrinkage data obtained by dilatometry experiments was collected and analyzed to help understand the densification and the sintering behaviors in terms of particles size and heating rate. The master sintering curve (MSC) model was used to quantify the effects of particle sizes. In addition, we investigated the microstructure evolutions in terms of particles sizes.open1186sciescopu

Characteristics of Hot Extruded P/M Aluminum Alloy when Using the Rapidly Solidified Powder SWAP Process

The characteristics of hot extruded aluminum alloy when using the rapidly solidified powder Spinning Water Atomization Process (SWAP) have been investigated. SWAP is one of advanced powder processing technologies to prepare high-performance powder particles with fine microstructures. In this study, A7075 aluminum alloy powder were produced by SWAP, and no intermetallic compound was detected in the raw powder. Microstructures and micro-hardness dependence on annealing temperature has been examined. Mechanical properties of the powder metallurgy (P/M) aluminum alloys consolidated by hot extrusion were superior to those of wrought alloys using ingot billets. A7075 wrought P/M alloys via T5 heat treatment show yield stress of 370 MPa and elongation of 15 % at the extrusion temperature of 623 K