PHONOLOGICAL PROCESSING OF STRESS BY NATIVE ENGLISH SPEAKERS LEARNING SPANISH AS A SECOND LANGUAGE

One feature of Spanish that presents some difficulties to second language (L2) learners whose first language (L1) is English concerns lexical stress. This study explores one aspect of the obstacle these learners face, weak phonological processing routines concerning stress inherited from their native language. Participants were L1 English L2 learners of Spanish. The experiment was a sequence-recall task with auditory stimuli minimally contrasting in stress (target) or segmental composition (baseline). The results suggest that learners are more likely to accurately recall sequences with stimuli contrasting in segmental composition than stress, suggesting reduced phonological processing of stress relative to a processing baseline. Furthermore, an increase in proficiency—assessed by means of grammatical and lexical tests—was found to be modestly associated with an increase in the accuracy of processing stress. We conclude that the processing routines of native English speakers lead to an acquisitional obstacle when learning Spanish as a L2.

A Research on Stress-Induced Deformation of Thin Copper Substrate in Double-Sided Lapping

Double-sided lapping is an ultra-precision machining method capable of obtaining high-precision surface. However, during the lapping process of thin pure copper substrate, the workpiece will be warped due to the influence of residual stress-related, including the processing stress and initial residual stress, which will deteriorate the flatness of the workpiece and ultimately affect the performance of components. In this study, finite element method (FEM) was adopted to study the effect of residual stress-related on the deformation of pure copper substrate during double-sided lapping. Considering the initial residual stress of the workpiece, the stress caused by the lapping and their distribution characteristics, a prediction model was proposed for simulating workpiece machining deformation in lapping process by measuring the material removal rate of the upper and lower surfaces of the workpiece under the corresponding parameters. The results showed that the primary cause of the warping deformation of the workpiece in the double-sided lapping is the redistribution of initial residual stress caused by uneven removal of double-sided material. The finite element simulation results were in good agreement with the experimental results.

Stress assignment in reading aloud in Spanish

Correct stress assignment is a requirement for fluent reading in alphabetic languages. This study focuses on two nonlexical mechanisms at the core of stress assignment. In particular, the use of a default stress pattern (e.g., penultimate stress) and the Spanish stress mark. In Experiment 1, participants read aloud words and pseudowords with different stress types (on the antepenultimate or the penultimate syllable), and with or without a stress mark. Results showed longer reaction times (RTs) for words and pseudowords with antepenultimate stress. However, as words with antepenultimate stress always have a stress mark, it could be argued that stress type differences could be due to the presence of the stress mark. In Experiment 2, using a priming procedure participants read aloud words and pseudowords in pure versus mixed stress blocks. Again, words and pseudowords with antepenultimate stress were read slower (longer RTs), suggesting that previous differences were due to stress mark rather than stress type. These results indicate that processing stress marks is cognitively demanding when reading in Spanish.

Superplasticity of Aerospace 7075 (Al-Zn-Mg-Cu) Aluminium Alloy Obtained by Severe Plastic Deformation

The 7075 (Al-Zn-Mg-Cu) aluminium alloy is the reference alloy for aerospace applications due to its specific mechanical properties at room temperature, showing excellent tensile strength and sufficient ductility. Formability at high temperature can be improved by obtaining superplasticity as a result of fine, equiaxed and highly misoriented grains prone to deform by grain boundary sliding (GBS). Different severe plastic deformation (SPD) processing routes such as ECAP, ARB, HPT and FSP have been considered and their effect on mechanical properties, especially at intermediate to high temperatures, are studied. Refined grains as fine as 100 nm and average misorientations as high as 39o allow attainment of high strain rate superplasticity (HSRSP) at lower than usual temperatures (250-300oC). It is shown that increasing misorientations are obtained with increasing applied strain, and increasing grain refinement is obtained with increasing processing stress. Thus, increasing superplastic strains at higher strain rates, lower stresses and lower temperatures are obtained with increasing processing strain and, specially, processing stress.

Mechanical Behavior After Stress Relaxation in PVDF

This study presents the mechanical properties evaluation of two commercial grades of PVDFs, which were extruded with the same parameters but with different cooling temperatures. After processing, stress relaxation with 7% strain was imposed and tensile properties were measured. The cooling temperature after extrusion were 4°C, 23°C and 80°C. Then, the PVDFs were submitted to stress relaxation at 23°C and 7% strain. The as processed and after relaxation samples were characterized by FTIR, XRD, DSC and tensile tests at 23°C. The stress relaxation at 23 °C resulted in no change in volume fraction of crystallinity for PVDF A and B. The XRD and FTIR, for both PVDFs, showed that the crystalline phases were the same, for all cooling conditions and did not change after the stress relaxation. The tensile properties at room temperature showed that the yield stress was a little affect by the cooling temperature, while Young’s Modulus and yield strain were insensible to the cooling temperature. After the stress relaxation, these three tensile properties were slightly affected for both grades.

Magnetic properties of silicon steel sheet core with different processing stress

The motor core including a rotor core and a stator core, which is made from silicon steel sheets. Iron loss increases during fixation of the stator core, e.g., by interlocking, welding, and shrink fitting installation. In this paper, the magnetic properties changes by each processing such as wire cutting, punching, interlocking and shrink fitting are investigated. Iron loss of the toroidal cores using punching, interlocking and shrink fitting are increased from 1.16 W/kg to 1.56 W/kg (34.4 % increased) at 50Hz, and from 21.1 W/kg to 27.5 W/kg (30.3 % increased) at 400 Hz compared with iron loss of wire cut toroidal core.

A SCIENTIFIC EVENING WITH N.A. BERNSTEIN, R.M. YERKES, J.D. DODSON AND D.O. HEBB

Author compares various models of relation between stress and efficiency of a motor operation, described with the Inverted-U Principle (IUP), Multidimensional Theory of Anxiety (MTA) and Catastrophe Model of Anxiety (CMA). He presents the “classical” theory, invented by R.M. Yerkes and J.D. Dodson in 1908, and modified significantly by D.O. Hebb in 1955. The latter is commonly known as the Inverted-U Principle (IUP). Author focuses his analyses on two factors determining the efficiency of a motor operation: cognitive factor (depth of information processing) and temporal factor (speed of information processing). Stress, of multimodal nature, may either stimulate, or deteriorate the efficiency of a motor operation just being performed. One of the possible descriptions of the structure of a motor operation bases on the theory invented by N.A. Bernstein (Brain Skyscraper – BS). Its continuation enabled creation of two other scientific models, the Modalities’ Ladder (ML) and the Movements’ Management Matrix (MMM). They make a specific perspective enabling joining the theories concerning stress-efficiency relation. This perspective unveils two mechanisms of efficiency deterioration: hypervigilance and hypovigilance, and, consequently, their different products: mistake, proper execution, choking and collapse. Finally, author remarks that the already long known theories may still include great resources of scientific explainability, and that the main task of science is not absolutely true mirroring of reality, but creation of its simplified models. They should be comprehensible enough to be useful in practice. This concerns also the issues of rather complex relation between stress and efficiency in a motor operation.