512 research outputs found

    Treatment of DomesticWastewaterwith Simultaneous Electricity Generation in Microbial Fuel Cell under Continuous Operation

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    In order to apply microbial fuel cell (MFC) process more practically in wastewater treatment, both power generation and removal of chemical oxygen demand (COD) were examined in an air-cathode MFC fed with domestic wastewater under continuous operation. At a hydraulic retention time (HRT) of 2.0 h, the air-cathode MFC was able to generate electricity from domestic wastewater with a maximum power density of P = 103 2 mWmā€“2 (5772 mW mā€“3) and an average Coulomb efficiency (CE) of 18.4%; meanwhile, to achieve an average COD removal up to 71 %. Increasing HRT from 2h to 10ā€“30 h was found to be more effective for COD removal, however, instability in voltage output was also observed. An increased power generation of 1734mW mā€“2 (9648 mW mā€“3) was obtained with the aid of NaCl addition at a mass fraction of w = 2.4 %, because of an elevated conductivity of the solution with accord internal resistance of 227 0

    Quantum logic between atoms inside a high Q optical cavity

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    We propose a protocol for conditional quantum logic between two 4-state atoms inside a high Q optical cavity. The process detailed in this paper utilizes a direct 4-photon 2-atom resonant process and has the added advantage of commonly addressing the two atoms when they are inside the high Q optical cavity.Comment: 8 pages, 3 figs. submitte

    Statistical properties of autonomous flows in 2D active nematics

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    We study the dynamics of a tunable 2D active nematic liquid crystal composed of microtubules and kinesin motors confined to an oilā€“water interface. Kinesin motors continuously inject mechanical energy into the system through ATP hydrolysis, powering the relative microscopic sliding of adjacent microtubules, which in turn generates macroscale autonomous flows and chaotic dynamics. We use particle image velocimetry to quantify two-dimensional flows of active nematics and extract their statistical properties. In agreement with the hydrodynamic theory, we find that the vortex areas comprising the chaotic flows are exponentially distributed, which allows us to extract the characteristic system length scale. We probe the dependence of this length scale on the ATP concentration, which is the experimental knob that tunes the magnitude of the active stress. Our data suggest a possible mapping between the ATP concentration and the active stress that is based on the Michaelisā€“Menten kinetics that governs the motion of individual kinesin motors.Theoretical Physic

    Entanglement, quantum phase transition and scaling in XXZ chain

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    Motivated by recent development in quantum entanglement, we study relations among concurrence CC, SUq_q(2) algebra, quantum phase transition and correlation length at the zero temperature for the XXZ chain. We find that at the SU(2) point, the ground state possess the maximum concurrence. When the anisotropic parameter Ī”\Delta is deformed, however, its value decreases. Its dependence on Ī”\Delta scales as C=C0āˆ’C1(Ī”āˆ’1)2C=C_0-C_1(\Delta-1)^2 in the XY metallic phase and near the critical point (i.e. 1<Ī”<1.31<\Delta<1.3) of the Ising-like insulating phase. We also study the dependence of CC on the correlation length Ī¾\xi, and show that it satisfies C=C0āˆ’1/2Ī¾C=C_0-1/2\xi near the critical point. For different size of the system, we show that there exists a universal scaling function of CC with respect to the correlation length Ī¾\xi.Comment: 4 pages, 3 figures. to appear in Phys. Rev.

    Dynamic skin deformation using finite difference solutions for character animation

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    We present a new skin deformation method to create dynamic skin deformations in this paper. The core elements of our approach are a dynamic deformation model, an efficient data-driven finite difference solution, and a curve-based representation of 3D models. We first reconstruct skin deformation models at different poses from the taken photos of a male human arm movement to achieve real deformed skin shapes. Then, we extract curves from these reconstructed skin deformation models. A new dynamic deformation model is proposed to describe physics of dynamic curve deformations, and its finite difference solution is developed to determine shape changes of the extracted curves. In order to improve visual realism of skin deformations, we employ data-driven methods and introduce skin shapes at the initial and final poses into our proposed dynamic deformation model. Experimental examples and comparisons made in this paper indicate that our proposed dynamic skin deformation technique can create realistic deformed skin shapes efficiently with a small data size

    The Vacuum System of HIRFL

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    AbstractThe vacuum system of Heavy Ion Research Facility in Lanzhou (HIRFL) is a large and complex system. HIRFL consists of two ECR ion sources, a sector focus cyclotron (SFC), a separate sector cyclotron (SSC) and a multi-purpose cooling storage ring system which has a main ring (CSRm) and an experiment ring (CSRe). Several beam lines connect these accelerators together and transfer various heavy ion beams to more than 10 experiment terminals. According to the requirements of the ion acceleration and ion lifetime, the working pressure in each accelerator is different. SFC is nearly 50 years old. After upgrade, the working pressure in SFC is improved from 10-6mbar to 10-8mbar. The pressure in SSC which was built in the 1980s reaches the same level. The cooling storage ring system with a length of 500m came into operation in 2007. The average pressures in CSRm and CSRe are 5Ɨ10-12mbar and 8Ɨ10-12mbar respectively. Different designs were adopt for vacuum system of a dozen beam lines to meet specific requirement of each experiment terminal. Along with the extensive development of the heavy ion researches and applications, new accelerators of HIRFL are under construction. The vacuum system of the new machines will be designed and constructed followed the overall schedule

    Exploring disparities in acute myocardial infarction events between Aboriginal and non-Aboriginal Australians: roles of age, gender, geography and area-level disadvantage

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    We investigated disparities in rates of acute myocardial infarction (AMI) between Aboriginal and non-Aboriginal people in the 199 Statistical Local Areas (SLAs) in New South Wales, Australia. Using routinely collected and linked hospital and mortality data from 2002 to 2007, we developed multilevel Poisson regression models to estimate the relative rates of first AMI events in the study period accounting for area of residence. Rates of AMI in Aboriginal people were more than two times that in non-Aboriginal people, with the disparity greatest in more disadvantaged and remote areas. AMI rates in Aboriginal people varied significantly by SLA, as did the Aboriginal to non-Aboriginal rate ratio. We identified almost 30 priority areas for universal and targeted preventive interventions that had both high rates of AMI for Aboriginal people and large disparities in rates

    A survey of partial differential equations in geometric design

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    YesComputer aided geometric design is an area where the improvement of surface generation techniques is an everlasting demand since faster and more accurate geometric models are required. Traditional methods for generating surfaces were initially mainly based upon interpolation algorithms. Recently, partial differential equations (PDE) were introduced as a valuable tool for geometric modelling since they offer a number of features from which these areas can benefit. This work summarises the uses given to PDE surfaces as a surface generation technique togethe

    Highly Efficient, Stable, and Ductile Ternary Nonfullerene Organic Solar Cells from a Two-Donor Polymer Blend

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    Organic solar cells (OSCs) are one of the most promising costā€effective options for utilizing solar energy, and, while the field of OSCs has progressed rapidly in device performance in the past few years, the stability of nonfullerene OSCs has received less attention. Developing devices with both high performance and longā€term stability remains challenging, particularly if the material choice is restricted by rollā€toā€roll and benign solvent processing requirements and desirable mechanical durability. Building upon the ink (toluene:FTAZ:ITā€M) that broke the 10% benchmark when bladeā€coated in air, a second donor material (PBDBā€T) is introduced to stabilize and enhance performance with power conversion efficiency over 13% while keeping toluene as the solvent. More importantly, the ternary OSCs exhibit excellent thermal stability and storage stability while retaining high ductility. The excellent performance and stability are mainly attributed to the inhibition of the crystallization of nonfullerene smallā€molecular acceptors (SMAs) by introducing a stiff donor that also shows low miscibility with the nonfullerene SMA and a slightly higher highest occupied molecular orbital (HOMO) than the host polymer. The study indicates that improved stability and performance can be achieved in a synergistic way without significant embrittlement, which will accelerate the future development and application of nonfullerene OSCs

    A theoretical and empirical investigation of nutritional label use

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    Due in part to increasing diet-related health problems caused, among others, by obesity, nutritional labelling has been considered important, mainly because it can provide consumers with information that can be used to make informed and healthier food choices. Several studies have focused on the empirical perspective of nutritional label use. None of these studies, however, have focused on developing a theoretical economic model that would adequately describe nutritional label use based on a utility theoretic framework. We attempt to fill this void by developing a simple theoretical model of nutritional label use, incorporating the time a consumer spends reading labels as part of the food choice process. The demand equations of the model are then empirically tested. Results suggest the significant role of several variables that flow directly from the model which, to our knowledge, have not been used in any previous empirical work
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