8,205 research outputs found

    Thermal analysis comparison between two random glass fibre reinforced thermoplastic matrix composites bonded by adhesives using microwaves: preliminary results

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    [Abstract]: This paper compares the thermal analysis of two types of random glass fibre reinforced thermoplastic matrix composites joined by adhesives using microwave energy. Fixed frequency, 2.45 GHz, microwave facility is used to join thirty three percent by weight random glass fibre reinforced polystyrene composite [PS/GF (33%)] and thirty three percent by weight random glass fibre reinforced low density polyethylene composite [LDPE/GF (33%)]. The facility used is shown in Figure 1. With a given power level, the composites were exposed to various exposure times to microwave irradiation. The primer or coupling agent used was 5-minute two-part adhesive. The heat distribution of the samples of the two types of composites was analysed and compared. The relationship between the heat distribution and the lap shear strength of the samples was also compared and discussed

    Dynamical Linear Response of TDDFT with LDA+U Functional: strongly hybridized Frenkel excitons in NiO

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    Within the framework of time-dependent density-functional theory (TDDFT), we derive the dynamical linear response of LDA+U functional and benchmark it on NiO, a prototypical Mott insulator. Formulated using real-space Wannier functions, our computationally inexpensive framework gives detailed insights into the formation of tightly bound Frenkel excitons with reasonable accuracy. Specifically, a strong hybridization of multiple excitons is found to significantly modify the exciton properties. Furthermore, our study exposes a significant generic limitation of adiabatic approximation in TDDFT with hybrid functionals and in existing Bethe-Salpeter-equation approaches, advocating the necessity of strongly energy-dependent kernels in future development.Comment: 5 pages, 2 figure

    The Effect of Wage Subsidies on Piece Rate Workers: Evidence from the Penny Per Pound Program in Florida

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    This paper studies a fair trade program in which consumers provide a wage subsidy (bonus) to piece-rate tomato pickers. The total subsidy—determined by sales to participating buyers—is divided among workers based on their relative output: a worker who produces more gets a larger share of the bonus. Although seemingly mimicking the existing piece-rate pay scheme, the mechanism associated with the bonus payment is really a relative performance evaluation, as the size of total bonus is exogenous and invariant to workers' effort. Therefore, for a given sized subsidy, the combined total (or per worker average) utility gains would become the largest if the workers keep their efforts at the pre-program level. Empirical analysis shows that worker effort (and hence productivity) increases substantially in response to the program, suggesting that currently, workers' combined gains per dollar of subsidy are not being maximized

    Variable frequency microwave (VFM) processing facilities and application in processing thermoplastic matrix composites

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    Microwave processing of materials is a relatively new technology advancement alternative that provides new approaches for enhancing material properties as well as economic advantages through energy savings and accelerated product development. Factors that hinder the use of microwaves in materials processing are declining, so that prospect for the development of this technology seem to be very promising. The two mechanisms of orientation polarisation and interfacial space charge polarisation, together with dc conductivity, form the basis of high frequency heating. Clearly, advantages in utilising microwave technologies for processing materials include penetration radiation, controlled electric field distribution and selective and volumetric heating. However, the most commonly used facilities for microwave processing materials are of fixed frequency, e.g. 2.45 GHz. This paper presents a state-of-the-art review of microwave technologies, processing methods and industrial applications, using variable frequency microwave (VFM) facilities. This is a new alternative for microwave processing

    Is China’s Pollution the Culprit for the Choking of South Korea? Evidence from the Asian Dust

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    This paper studies the impact of air pollution spillover from China to South Korea. To isolate the effects of cross-border pollution spillover from that of locally generated pollution, we exploit within-South Korea and over-time variation in the incidence of Asian dust—a meteorological phenomenon exogenous to district-time cells in South Korea—together with temporal variations in China's air quality. We find that conditional on being exposed to Asian dust, increased pollution in China leads to increased mortality from respiratory and cardiovascular diseases in South Korean districts, with the most vulnerable being the elderly and children under five

    Initialization by measurement of a two-qubit superconducting circuit

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    We demonstrate initialization by joint measurement of two transmon qubits in 3D circuit quantum electrodynamics. Homodyne detection of cavity transmission is enhanced by Josephson parametric amplification to discriminate the two-qubit ground state from single-qubit excitations non-destructively and with 98.1% fidelity. Measurement and postselection of a steady-state mixture with 4.7% residual excitation per qubit achieve 98.8% fidelity to the ground state, thus outperforming passive initialization.Comment: 5 pages, 4 figures, and Supplementary Information (7 figures, 1 table
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