Fast calculation of carrier harmonic iron losses caused by pulse width modulation in interior permanent magnet synchronous motors

Normal calculation of the carrier harmonic iron losses (CHILs) brought by the pulse width modulated (PWM) voltage source inverter in interior permanent magnet synchronous motors by the time-stepping finite-element analysis (TSFEA) with short time steps is very time-consuming. In this study, a novel method for fast calculation is proposed, where a combination of the frozen differential reluctivity tensor method and the time-harmonic finite-element analysis is proposed to investigate the relationship between PWM voltage harmonics and the corresponding CHILs, with which the CHILs in stator and rotor are fastcalculated with the voltage harmonics in stator and rotor reference frames, respectively. Besides, the eddy current reaction effect in electrical steel sheets on the CHILs at high frequency is considered by an analytical method and validated with the TSFEA. The results reveal that eight parameters are recommended to calculate the CHILs at different operating conditions, which vary with the fundamental current. Consequently, the CHIL map over the entire operating conditions can be fastcalculated using the analytical spectra of the PWM voltages. Experiment on a specimen is conducted to validate the accuracy of the proposed method, which shows it depends on whether the equivalent differential permeability of the silicon steel can be accurately modelled.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.DC systems, Energy conversion & Storag

Quantum information entropies for an asymmetric trigonometric Rosen–Morse potential

Shannon entropy for the position and momentum eigenstates of an asymmetric trigonometric Rosen–Morse potential for the ground and first excited states is evaluated. The position and momentum information entropies Sx and Sp are calculated numerically. Also, we find that S1 x is obtained analytically and increases with the potential depth and width. Some interesting features of the information entropy densities ρs (x) and ρs (p) are demonstrated graphically. The Bialynicki-Birula–Mycielski inequality is also tested and found to hold good

Effect of CA bacteria on the carbonation process of γ-C2S

Carbonation has been proven to be a promising way to improve the mechanism properties and durability of steel slag products. CA bacteria can promote the hydration of CO2. In this study, one kind of alkali-resistant CA bacteria was chosen to investigate its effects on the carbonation process of γ-C2S. Results showed that bacteria could increase the compressive strength of carbonized γ-C2S by 19.0%. Main products of carbonized γ-C2S were vaterite, calcite and SiO2 gel. The addition of bacteria could only accelerate the deposition of calcium carbonate, while hardly changing the types and properties of the carbonation products. Additionally, accelerated carbonation makes it harder for the carbon dioxide to diffuse inward, leading to the decline of accelerating carbonation effect. However, CA bacteria could change the morphology of calcium carbonated during the carbonation process of β-C2S and further accelerate the hydration process of β-C2S. The pore structure can also be refined with the incorporation of bacteria

Utilization of biomass fly ash in alkali-activated materials

This paper investigated the feasibility of using biomass fly ash (BFA) to prepare alkaliactivated slag and fly ash paste. The reference mixture was alkali-activated slag and coal fly ash (CFA) paste with a slag-to-coal fly ash ratio of 50/50. In other mixtures, coal fly ash was replaced at 40% and 100% with BFA, respectively. The results showed that the incorporation of BFA accelerated the setting of the paste, while its impact on the compressive strength was minor. XRD and FTIR results indicated that the BFA participated in the reaction process. BFA showed potential use as CFA replacement in synthesizing alkali-activated materials, which would pave a way for the valorisation of BFA

Mitigating the autogenous shrinkage of alkali-activated slag by internal curing

Alkali activated slag (AAS) has shown promising potential to replace ordinary Portland cement as a binder material. Synthesized from industrial by-products, AAS can show high strength, thermal resistance and good durability. However, AAS has been reported to exhibit high autogenous shrinkage. Autogenous shrinkage is a critical issue for building materials since it can induce micro- or macro-cracking when the materials are under restrained conditions. Hence, this work aims at mitigating the autogenous shrinkage of AAS by means of internal curing. The influences of internal curing on microstructure formation and autogenous shrinkage are investigated. The results show that internal curing provided by superabsorbent polymers is a promising way to reduce the autogenous shrinkage of AAS

The Effect of Psychological Scarcity on Health Decisions of Rural Residents in China: Preliminary Results

Economic studies have shown that living in poverty may produce a subjective feeling of scarcity, which affects people's cognitive functions and decision-making. Understanding this mechanism could inform healthcare designers on designing inclusive health interventions by considering the psychological scarcity and limited cognitive resources of impoverished individuals. We conducted a psychological experiment to test the impact of psychological scarcity on cognitive function and health decisions of rural residents in China. We randomly assign participants to two financial scenarios (hard vs. easy) with the technique of priming to induce their immediate financial worries. Then we measure cognitive function using Raven’s Progressive Matrices and uncover their decision-making priorities with a budget allocation task. 301 participants finished the study and 264 were included in the main analysis. The results show that both immediate financial worries and cumulative poverty have negative effects on participants’ cognitive performance. Responses to scarcity could lead to attentional focus on limited resources, thereby neglecting long-term health consequences, particularly for the lower income group. Based on the findings, we suggest a number of human factors design considerations that are critical to successful healthcare design.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Ergonomics and Desig

Significance and pedogenic variability of phytogenic mounds on the Loess Plateau of China

Phytogenic mounds, a mound-type microtopography, always develop around plants as an interaction of individual plants with erosion, sedimentation, and bioturbation processes in many different ecosystems. In this study, the spatial variation of soil physical, chemical and biological properties was examined in different parts of phytogenic mounds and intercanopy surfaces on different slope gradients on the Loess Plateau of China. The key indicators that affect soil properties were identified. The results revealed that soil properties on mounds underwent a subtle change compared to intercanopy surfaces on alpha 46.6% slopes. The spatial variability of soil properties did not obviously change among different mound parts on alpha 46.6% slopes. Soil chemical and biological variables were positively correlated. However, the physical properties correlated negatively with other variables. The soil available nutrient, moisture, and microbial activity were the key indicators that affected soil quality. The findings all indicate that phytogenic mounds play an important role in preventing soil deterioration and influence long-term ecosystem processes on the Loess Plateau of China. (C) 2017 Elsevier Ltd. All rights reserved